I've been interested ever since I had a wonderful sous-vide chicken at Eleven Madison a few years ago. I had looked into it in a somewhat desultory fashion for a while but a thread on another board about:
http://www.chefscatalog.com/product/258 ... -Oven.aspx
and a tax refund check convinced me to give a go. Aside from the above I also picked up a Foodsaver to do the vacuum sealing. That is the less expensive option, this guy went all out:
http://extremecookingblog.com/2010/02/m ... de-set-up/
The real disadvantage of the Foodsaver is that you can't seal things with liquids as they get sucked out during the vacuum sealing process. The workaround is to freeze any liquids you want to use before putting them in the bag.
As most of you probably know the basic concept of sous-vide cooking is to seal the food and flavorings in a vacuum sealed bag and cook it in a water bath heated to your goal internal temperature. So instead of, for example, roasting a meat at 350 degrees until it reaches an internal temperature of 130 you would cook it at 130 degrees for a longer period of time. It is much more forgiving since the meat will not overcook (never get above 130 degrees in this example).
This has several advantages
1. timing - you can leave most dishes in the water bath for an extra few hours without problems
2. texture - it will usually result in a more velvety texture than other methods
3. the long slow cooking allows seasonings to permeate the meat (or vegetable, etc.). a crockpot is probably the closest equivalent.
4. it's a non-fat method of cooking which nonetheless can impart a lot of flavor (good for those of us who are dieting)
If appropriate you can do a quick sear at high heat after it's done to get maillard reaction flavors as well.
It's not a substitute for other methods but it is an option that can do things that other methods cannot accomplish.
This is the famous eGullet thread:
http://forums.egullet.org/index.php?/to ... equipment/
So for my very first "let me figure out how this setup works" experiment I just bought a package of 3 bone-in store brand chicken breasts. I'd normally expect these to be dry and tasteless after cooking. I sealed them in bags using the Foodsaver - one with a bay leaf under the skin and some tarragon, one with some dried oregano and one with some onion and garlic powder. Filled the sous-vide machine with water, let it heat to the recommended temperature, and dropped the bags in for 3 hours.
On opening the bags my real surprise was that it really smelled like chicken. What flavor there was in the breasts had not escaped. The bay leaf and tarragon had permeated the meat and the the meat was tender and moist and, most interestingly, cooked evenly throughout. The narrow part of the breat wasn't overcooked and the thick part wasn't undercooked. And while I normally throw out chicken breasts as not having flavor it was an enjoyable meal with a glass of Burgundy and some sauteed asparagus. Had I used better ingredients I'd expect the results to be even better.
I just had the breast flavored with oregano cold for lunch. It had a nice oreganoish flavor to it and was still moist. So preliminary results are quite positive

I hope to move onto shortribs this weekend, depending on my schedule.