I have a vertex 4 in my laptop, have had no reliability problems with it. Even though I personally have had no problems does not mean they are good. They need to improve their reputation of building reliable ssd's. They are known to have some of the worst reliability in the business.Their speed is very good.
For a desktop user, even one with high demands, a sandforce 2, or the latest indilinx, marvel or intel controller all provide great performance. I'd say 20% difference in performance between them and the only area to really improve on for SATA 3 would be small queue depth 4K transfer speeds.The difference in speed with using my old X25-M G2 80GB and the latest top end SATA3 SSD would probably only shave a few seconds off boot time or time to install windows updates, etc.
Of course for file transfers and sequential write intensive activities the new SSD would be much faster. But comparing early high end SATA 3 to the latest high end SATA3 SSDs there isn't much difference.
I feel confident with buying used because I'd buy 1 that has a track record for reliability.A well engineered one shouldn't fail for 20+ years or if it has 100s of TBs written to it.
Had my Vertex 4 256GB for about a year now, with nothing but excellence, especially where performance is concerned.As for the comment a few up about getting a second hand SSD... well that's the stupidest thing I've heard all day. The hard drive (especially if it's an SSD) is the LAST thing you want to buy second hand. Power supply comes pretty close. Some things you just don't buy second hand. You can save your money, but you may not be able to save your data.I get the feeling some smart alec is going to comment about backups now...
An SSD has no moving parts, doesn't run hot. What is there to wear out besides write cycles? The write cycles can be monitored in the S.M.A.R.T. report. I'd say it's unwise to buy a used hard drive but much smarter to buy a used SSD with a DOA gurantee. My Intel G2 SSD has about 3 years of on time with 20.52TB written to it, very reliable. And yes of course backups are good for any media you use.