My vote is for front edge so all shadows will fall behind what you're doing. If you put them in the back, shadows will fall where you're working. That's my theory, at least. Interested to hear what others have to say.
Lisa

Undercabinet lights should be installed toward the front. If they are installed toward the back, they will be shedding light mostly on your backsplash, rather than on your counter. So, installing toward the front means light shed evenly over your counter where it's needed. If you try to compromise and install them in the middle, you will still be wasting some of your light on the backsplash, so try to install them toward the front. Furthermore, the strips installed toward the front will be less visible or invisible. If the strips are installed toward the back, you will be able to see the strips, especially if you are sitting, but even not sitting, you will see the strips if they're installed toward the back.

do you have angled corner cabinets? I do and am wondering if the lights should go in the middle of those or also in the front. Not wanting to hijack, but anybody know the answer?

I have mine at the back, and have no shadow problems at all. Nor do they just light the backsplash. They work perfectly (I think there's a light angle to the unit).
I have an angled corner cabinet and the light is mounted slightly behind the middle on that one. It lines up better that way with the others.

My Xenon lights have a diffuser cover on the unit - perhaps this is what ensures an even, effective work light?

We were told that you cannot put the Xenon lights in the front without a transformer. Evidently they (the people at the light store) said you would see the wiring and it would look terrible.

That said, we were going to buck their advice - we aren't so meticulous that we balk at the thought a wire UNDER the cabinet, for Pete's sake, but I just picked up my Xenon light strip at Lowe's tonight and saw a product I hadn't seen at the other Lowes, and I love it. It's a Xenon under counter strip on a swivel so you mount it at the back as recommended and then aim the light wherever on the counter you want it to land. That's what I picked up. And they were actually a few dollars cheaper than the normal Xenon strips.

From the Rensselaer Polytechnic Institute's Lighting Research Center (according to the website, the leading university-based research center devoted to lighting and offering one- and two-year master's programs and a Ph.D. program in lighting.)--I couldn't get the link to work so I'll copy it below:

"Under-cabinet lighting should not be glaring to anyone, especially someone in a seated position elsewhere in the room. Fixtures mounted under the cabinets should be well shielded; a piece of trim molding approximately 1 in. wide should be added to the bottom of the cabinet. Installation of the fixture toward the front of the cabinet or shelf is generally recommended. This produces the most even light distribution on both the countertop and the backsplash. This location is also useful in reducing the potential for direct view of the light source, typically resulting in the least glare."

And my electrician says tha back - though I have not asked yet why - and I am sure he will go with what I ask.

dcwesley, my electrician told me front? Mine are in the front. If I didn't have undercab trim, I would have moved them to the middle to make them less visible.

My contractor wants to use puck lighting. Are the stips better than the puck lighting?

Kitchenconfidential,
depends on if you can see in spotlights. If they are close enough that the light on the counter is even, it should be just the same. I can't take that risk as I can not seem to focus on anything with the light/shadow/light/shadow effect of any spotlights. Can't see anything in department stores, lol.
Lisa

We put ours in last week. We put them 1.5" in from the front. The electrician said he always puts them in the back to hide the wiring. Well, the light strips hide the wiring. We found 15/16" strips that do not need a transformer and you cannot see the strips or the wiring. The electrician was very impressed with them and agreed they were in the best position. We also have a corner lazy susan and positioned that strip the same as the others. We do not have a light rail....Take a look at Pegasus...really great lights at a good price.

I do not understand the people who are saying the wiring will be less visible if installed toward the back. Everything--the strips and the wiring--will be more visible in the back. If you place the strips in the front, everything is hidden by the light rail. Placed toward the back, they will be visible, especially when you are seated. I quoted the Rensselaer Institute above--they have Masters/Phd programs devoted to studying lighting, so I would tend to take their word for it. And, as Jsol pointed out, there shouldn't be that much wiring to hide (I have to crane my neck up to see the small piece of wiring visible on my xenon strips), and the little wiring there is should be mostly tucked against the strips.

Kitchenconfidential2 - Just MHO, but I am not a fan of puck lighting because I don't like that it sheds circles of light on the countertop rather than the more even light of strips. I didn't understand what Lisalists says about the distance above the countertop making a difference. There isn't a lot of variation in distance from countertop to lights, typically 16-18", so I don't think distance in undercabinet lighting will change whether the pucks leave circles or not. But some people like the dramatic effect of circles of light on countertops at night. So that is a reason to prefer pucks over strips.

lisalists2000 and akchicago, thanks. I was concerned about that. For some reason, my GC and electrician say pucks are the way to go, but I am not liking it.

What is the best brand with the best lighting for undercabinet lighting, in your humble opinions?

Strips can be placed front, back, or center. They do different things to the counter and backsplash depending on where they are placed and the way the arc of light spreads.

At the back they can cause color-shift if the backsplash is a muted color so watch out for that.

There is no one right/wrong on placement though. It depends on the baffle somewhat and if you want more light in the front, center or rear of the counter.

Some uppers have no light rail, especially frameless. We put pucks down the center of Ikea frameless uppers. Electrician disguised the wiring with tape color-matched to the cabinet bottom. So wiring is no excuse as it can be made invisible.

Pucks give dark and light spots. Mine are halogen low-voltage and ok in the mudroom but so hot (WAC) they actually heat the room during the winter if left on for more than an hour. I would only do them inside cabinets again, not outside as the light is not even.

In the kitchen in my we have an excellent low-profile Task undercab light in the front of a platerack with a shallow light rail (piece of wood that hides the fixture). It works great. I linked it on the other xenon thread.

The bulbs are expensive to replace but they have very, very long lives.

The wiring isn't visible for mine, because it was placed in the wall and comes through just below the cabinet: the light unit completely covers it.

And I don't have a light rail either, because I don't care for the look. Still not experiencing any glare from my rear-mounted lights though!

As mentioned above, I don't have a light rail, because I dislike the look.

When did it become such a bad thing to have visible lighting? I mean, we don't all go "aargh! I can see the chandelier" about other lights, do we?

A well designed undercabinet unit can look sleek and unobtrusive. But I don't see why we have to insist on its being invisible.

Just musing.

rococogurl, I am not sure which link you were referring to. My GC is designing a wood cover piece so the lighting wires will not be visible. What is the brand and model of the light you are using?

Having a light rail is a nice refinement. Sounds like your KD is on top of it.

I used this one. There are less costly and very good options for sure (Kichler, Pegasus etc.) to compare.

What I liked about this one is that it comes in orderable lengths. At the bottom of the link there's a diagram that shows how the lens wraps. It's clear so there's maximum light. The alternatives would be fixtures with glass lenses that act as diffusers -- different type of light.

I was able to order direct and they spec'd a transformer that would work. It's been great for us.

Here is a link that might be useful: Task Undercabinet

Thanks. I'll talk to my GC about that.