I'm a bit of a anti SSD still. I see their benefits in laptops big time. But for desktops? I dunno. Reliability scares me. Longevity scares me a bit as well. And the cost vs capacity is too high. I'd just be getting one as a boot drive to have windows and the swap file on. Don't think i'd really get my money's worth.
Mostly though it's reliability and longevity for me. Too many reports of dead drives.
I believe most of the reliability issues are pretty much non-issues now. Write amplification on modern SSDs is likely a lot better now that TRIM and garbage collection are now standard. In addition, return rates on SSDs aren't significantly higher than HDDs at all. Intel's is 0.59% (IIRC) That's incredibly low for anything.
Regarding longevity, it takes years of constantly writing mass amounts of data to your drive to actually kill it. For example, a 256GB drive with 3000 P/E cycles can have 768TB written to it--that's ~52GB/day for 10 years, assuming a write amplification of 4 (higher than it probably will be).
Long story short: Stop worrying.