They're A LOT faster. Boot times are slashed, opening things from disk happens a lot faster.
I have nothing to back this up, but I don't think they're any less reliable than spinning disks. They may even be more reliable. The two issues are:
1) When an SSD fails, it is usually without warning and it is usually cooked. A SATA disk may fail but then work again on restart.
2) SSDs are more difficult to recover data from should you need to do it.
On machines I spend more than $500 on, I run my OS on an SSD and store my data on a removable hard disk. If my SSD craps, I have to rebuild stuff, but if I need something immediately I can grab my data disk and plop it into another computer. This has been handy a couple of times on work computers where I usually won't get it replaced for a few days. Eject the disk, throw it something else, I've got my stuff.
I've had two SSDs fail on me (and I don't know how my SATA disks) and I won't use anything but an SSD for my primary disk.