Advantages: Speed / Responsiveness
Disadvantage: Limited Size / Cost per GB
It will greatly improve your boot time (I've seen many state their boot time went from a few minutes to 30 seconds). It will impact the total responsiveness of programs when opening, since you are looking at 0.1 ms access times versus 10 to 12 ms with standard drives. RAID0 still sees the nice speed increase over a single drive but TRIM support becomes an issue with much. The improvement over a standard drive is good enough that their is no really need to run in RAID0... IMO
Difference from other post: If you are trying to build a fast responsive PC, a SSD is a most for that type of system... IMO. It will benefit in load times of games but outside of that you will not see a dramatic increase in FPS with going on a SSD. I've heard people say it shows a benefit in games like WoW in large battles, as it can process quicker than a standard hard drive, but I have no personal experience to confirm or deny the benefits.