I use it mostly for steak, though it is great for chicken and vegetables as well.

The best thing about it is that you can cook your steak to the exact doneness that you prefer. 125 rare, 130 medium rare, 135 medium and so forth. Simply seer properly afterwards and you get an amazing perfectly cooked steak. This, to me beats the reverse sear and Alton Brown (sear first, 500 oven to finish) techniques.

The second best thing is that the length of cooking doesn't affect the doneness level. 4 hours at 130 is still medium rare, except that the extended cook time breaks down the proteins further, so if your meat is a tough cut, time at temperature will tenderize it a bit, though it won't transform chuck into ribeeye.