I never remember which one of those means which kind of faucet, but I do know that one means the detachment point includes the knobby end plus a goodly amount of the faucet arm, and the other means mostly the knobby end detaches. My mom has one that includes a portion of the arm and I find it difficult to use: awkward to spray/rinse around the whole surface of the sink, difficult to spray anything towards the rear of the sink. I have one where just the end detaches, which pretty much fits in your hand. I find it easy to rinse down the side of the sink and chase stray bits of food and head them to the disposal. I guess it's the difference between something more maneuverable and something awkward.

Thank you very much, Suzannesl. I think you mean the pull down is more maneuverable. Can it be pulled out and spray the garbage can?

Sorry, but Suzannes1 is not 100% clear about what the differences are between the pull-out and the pull-down faucets. Much of the difference has to do with the reach and the height of the faucet, not solely the detachment end of it. Anyway, a pull-out reaches farther into the sink (you can get the measurements on any manufacturer's website), and the height is lower than a pull-down. A pull-out's sprayer points down, but at a slightly outward angle. A pull-down has the sprayer pointing straight down, its height is taller than a pull-out, and typically does not have as long a reach as a pull-down.

There are pros and cons of both types, and there is no "correct" choice - it depends upon what you like, the aesthetics of your kitchen, and most of all, what feels good in your hand. The very best thing you can do is go to a kitchen/bathroom showroom, and feel them for yourself. Also, if you have cabinets above your sink, check the height; a height constraint may eliminate the pull-downs for you.

Some people feel the pull-downs are more ergonomic when using the spray feature cause they point straight down. On the other hand, some have reported that the pull-downs are harder on the back because they are closer to the back of the sink, making your arm have to reach more in order to rinse something under the faucet. Also some people feel that the pull-downs that are close to the back of the sink leave more water puddling behind the sink. Other people like the pull-downs better because they like the aesthetics more. If you opt for a pull-down, make sure you get one with a magnet that will retract the head; otherwise you may get a dangling head that will be annoying.

I am going to link an old thread which sums up the pull-out and pull-down faucets quite thoroughly.

Here is a link that might be useful: Thread Called Pull-down vs. Pull-out Faucet

Here's a slightly less exhaustive take on the most important aspects of buying a faucet. Plus, Kohler's faucet design guy recommends pull-downs. What he has in his own home.

Here is a link that might be useful: Making Sense of Kitchen Faucets

Thank you very much, Akchicargo and rococogurl. A friend of mine bought a pullout from costco and complained that water flew back into the pullout hole in the faucet and got to the cabinet beneath. Should it be a concern?
Appreciate your help.

Jane--I've never heard an issue like your friend has. Either it's a horribly designed faucet, a lemon of an otherwise fine faucet line, or it was poorly installed. Hundreds and hundreds (thousands?) of us here have pulldowns. If that was an issue, we'd hear about it quickly!

Hi all, just browsing thru: I have a Delta pull down with a high goose neck and a deep sink. This allows easy filling of a bucket in the sink. I can imagine it might be a tight squeeze to divert it to a bucket on the counter. I might have to hold the bucket in the front. I think an extra long hose could be ordered.

Regarding the back spray leak issue, assuming the connection to the heads are the same, I can see this could be an issue. My pull down has a nice easy screw on connector that can become loose. Perhaps I just don't have it as tight as it is designed to be. Every year or so I notice that the water left in the head after shut off dribbles out rather than stoping immediately. I realized that air was getting in the hose. Now I just re-finger tighten the connector. If this happened with a pullout with the faucet on, the loose connection would allow some water to jet out of the connector and fall back down the housing into the cabinet. In a pull down, the housing points down into the sink and any leakage is almost unnoticed. Admittedly, I have never actually noticed water dribbling out the housing with the water running. But I do have complete correlation with the loose connector and the shut off dribbling faucet.

No concern whatsoever if properly installed. If you think about the dynamics of water flying back into the pullout, sounds impossible. More likely there was a leak or a flaw somewhere in the faucet.

Thank you very much for all your responses, which are very helpful.