well i personally use FL 9 and i think its the most user-friendly DAW out there. i could work around it with my eyes closed - i made 6 beats yesterday alone with it. its hard for me to give any cons because i either dont know any better or i can pretty much execute any beat idea i have in my mind with it.
ive dabbled with Reason - i think the general consensus is that Reason is the more advanced DAW but i cant really tell you by experience. all i know is its harder to learn than FL. I guess i havent invested too much time in it though.
i never used any other DAW. And imo "VSTs" should almost be more of a concern than what beat program you use - because DAWs all essentially do the same thing, it just depends on what YOU do with it.
some unknown producer landed a FL beat on ghostfaces last album...and i was reading about a techno producer overseas who got famous in a matter of months that strictly uses FL even though it tends to get a bad rep