I hit 2 handed for the first 10 years I played tennis, then switched in my early 20's and have hit a 1 handed backhand ever since. As with most choices, Ive found that there are tradeoffs. I feel like I have more range with the 1 hander (important for a short fat guy like me). I also feel like I get more power as I can generate more racquet head speed with the 1 hander. I'm much better at hitting on the run with the 1 hander. The slice and volley are easier and more natural using 1 hand (I could never hit a 2 handed volley anyway).
The biggest drawback has been shot preparation. I had a shorter backswing and a more compact stroke when using the 2 hander, which allowed me to take balls on the rise better, especially on the return of serve. My returns were much better using 2 hands. I also feel like I have slightly less control with the 1 hander, not quite as accurate, but not by much. I have a hard time hitting inside-out off the 1 handed backhand. If the ball stays down or bounces waist high, I can kill it with the 1 hander, but I have a harder time dealing with balls that bounce higher to my 1 handed backhand.
Just remember that if you do switch, don't expect to have a Henin-Hardenne backhand righ away, it takes a while to get used to positioning yourself to hit it.