I have just gone through my own decision hell.
Briefly, I will share my thoughts but others are more eloquent than I.
If you can get natural gas, many people love it. I loved it but I would have to have propane and was told it would still not really compare to natural gas.
If you are looking for 48", I don't believe induction is available in that, though you could add a 12" unit to a 36" unit to obtain that.
There are only a few induction that have auto-turn off hobs. Some think that is a deal breaker and others consider it simply a nice feature.

Type in "induction" in the search and read some of the nice threads already here and then perhaps you can post back on any specific questions.

There are no 48" induction cooktops;36" is the largest size.Any accurate info about installation has to be done once a particular cooktop is picked. Lots of threads on this google "gardenweb induction installation."

The largest gas "cooktops" are Miele at 42" and Dacor at 46".

There are plenty of 48" gas rangetops. The only ones that will compare to better induction cooktops are Capital Culinarian and Bluestar RNB.

See link below for gas vs induction threads.

Here is a link that might be useful: LINK

Thanks everyone.

Let me clarify. I am debating between a 48 inch BS or CC cooktop or an induction. Thermador is debuting an induction cooktop that is completely induction - no burner rings. The Thermador Freedom Induction Cooktop is the first full-surface induction appliance. According to Thermador "It features the flexibility of a natural-mapping user interface that intelligently recognizes cookware size, shape and position to deliver heat without boundaries."
It will be in the same price range as BS or CC.
Size of the induction top is not an issue because if I got a BS or CC it would be 48 to accommodate a grill and in the case of BS a french top. With induction the french top becomes a moot point, but I would miss the grill. But, that is another issue and not really relevant here.
What a really want to know is the pros and cons of induction versus open flame burners.

That particular Thermador unit is what is called "zoneless". It has something like 48 induction drivers below the surface. When you put a pan on it, the drivers sense the presence of the pan and the computer figures out the shape of the pan from the drivers that sense its presence. This means you can put any size or shape pan on the surface and the computer will do the rest. You can also slide the pan around and the computer will keep track of where the pan is located.

IIRC, there is a limit to the number of pans going at once, like 4 or 5 depending on the size of the unit (30" or 36").

It also means that you can put a rectangular grill pan on it successfully (steel, not aluminum).

For me it was easy, couldn't wait to get rid of gas. The ease of wiping a flat surface clean compared to scrubbing/scraping in, on, around and below heavy burners was a no brainer. Plus eliminating more heat emanating into the kitchen was a bonus. With the power and precision of induction, I just don't see the rationale for gas anymore. Unless, I guess, you're a die hard traditionalist, want the look, must roast peppers/marshmallows in your kitchen....???

Thank you everyone for the responses. I guess what I really want to know are there downsides to induction cooking?
My kitchen currently has two ranges - one gas, one electric. When I built my
kitchen 20 years ago, I wanted an electric oven for baking and gas burners. The only option was two ranges because I wanted a large capacity electric oven. Two years ago I replaced my gas range in a hurry and got a GE cafe gas model which I intensely dislike (uneven oven temps, poor simmer etc.) But it does give me access to gas burners. So the most frequently mentioned cons are a non issue for me.
I just called Thermador and the Freedom top will not be available until June or July. Since I need to replace my non functioning range before then, another question for me is pot sizes. I often have two or three oversize stock pots simmering at the same time (20 quart or more)- the bottoms are 12 -14 inches. Are there induction cooktops out there now that accommodate 3 large pots simultaneously? Any brand recommendations or ones to stay away from?

... Or, unless you live somewhere where electric power can be unreliable -- meaning occasionally you may not eat for a few days unless you have gas.

A point that has not been made clearly here (though I'm sure it's been discussed in the threads deeageaux linked above) is that you don't necessarily have to get one OR the other: It sounds like you have room for induction AND gas as well. This could be the best choice, depending on your (so far, unstated) individual needs and preferences.

I went induction and am t-1+ week to demolition and remodel.
The reasons I went induction
-Safety
-Control
-Don't like the smell of gas
-Added work surface

I wish I could have waited for the zoneless although probably out of price range

Also - induction choices are changing rapidly - so this is a relevant thread!

Disadvantages
-Griddle - still haven't found one that meets my needs - but do have an electric one but will miss my all clad double (which is aluminum)
-Special pans - my old aluminum will be stored in my basement for my "vacation home" of the future.

67 threads discussing your question. Many go into detail after detail comparing the two as well as conventional radiant electric.

Here is a link that might be useful: Induction vs gas threads

As far as I know, there isn't an induction unit out currently that will accomodate 3 12 inch stockpots at one time. My Miele will accomodate one 12 quart stockpot and two other 8-9 inch pans.

I love my induction cooktop, for the ease of maintaining even cooking temperatures, the power, and the absolutely effortless cleanup. If you have room for 48 inches of cooktop, you could do as some folks here have done and install an induction cooktop, with two additional gas burners next to it.

Cj

Thanks everyone. I found the threads people referenced very helpful. I especially liked the induction website. It had an incredible amount of information. In case anyone else needs large hobs, I found that Thermador makes an induction with a 13 inch hob (1-6, 2-7's, and a 9). MSRP is $3699.00 for one model and
$4,099.00 for another.

Ditto chac_mool.

I'm in the middle of going from electric to gas. There a number of stovetop-roasting operations that require an open flame (e.g. eggplant is incredible if your start out roasting over an open flame, and it's great for the final phulka with chapatis). Some of us like the visual cue of the flame.

But if I could truly start over including all new cookware, I'd get a 30" induction cooktop plus one gas burner ... maybe even the kind made for a wok. The efficiency benefits of induction are just unbeatable.

I found this quite interesting: Seems the Thermador Freedom Induction cook top got quite the review!
http://appliancebuyersguide.com/most-ridiculous-appliance-awards/

I purchased the 36" Bosch Induction cook top and cannot wait to use it. Europe has been using induction for a long time. Not sure why we haven't caught on yet. They love it and so do most people I know who do use them!