I have used FL Studio, Reason, and now just started using Ableton.
To me FL Studio is the easiest program to get into. Very ideal for beginners. But FL Studio is a very powerful program if you know what your doing with it. Which is why you have big name producers like MDL and Lex Luger using it. And why it took 9th Wonder a while to switch from FL to Pro Tools. IF I had to recommend a DAW for a starter, I would most def recommend it. When I first started out I used FL Studio.
Reason to me, is powerful for CREATION. What I mean by this is creating your own sounds. Sense reason doesn't allow VSTs you don't get the: Nexus and the Massive, with those already pre made awesome sounding synths, pianos, strings etc waiting for you to use.In Reason you have to make them yourself. So this program is ideal for those who like to tinker and make their own sounds for scratch.
Ableton Live, I just started using it so I cant say to much on it. But Its awesome for people who sample due to being able to Warp the samples and getting them on time. And its sort of like a MPC when your making your beat cause you can add and remove things on the fly. I'm hopeing to be able to make this my main DAW. I'm hopeing to fall in love with this program because I have heard nothing but good about it.
To me the BEST VSTs out there currently is FL STUDIO or Logic Pro. Sense I just made the switch to Ableton I cant say much about it yet. But if Im unable to use Ableton I most def will be going back to either FL STUDIO, or if I get a mac, Logic Pro.