I'd actually say it's not worth it - eggs in one basket approach (one fails, you lose it all). But if you keep them separate, then you minimize potential problems.
However, saying that, I am running a couple of intel's older SSDs in a RAID 0 for my OS and haven't had too many problems. My reasoning was because they're 80GB's, and I needed more than that for my C:. But if I could afford a single 240, I'd like that route best.
The speed gain doing a RAID0 with SSDs isn't night and day difference, but it is somewhat noticeable, none the less.