Quote from dcraig:
I think they would be very good for some usages. The average access times are ~ 0.1 msec compared to ~ 12 - 15 msec for consumer type hard disks. This makes for phenomenal I/O rates for database applications. You would need some serious raid setups for hard disk drives to go anywhere near what a good SSD can do.
Sequential read/write performance maybe around twice that of a conventional hard drive. But you can probably do much the same with two or three conventional disks in Raid 0 config.
The sequential throughput is approaching the limit of SATA II controllers, so that is not likely to improve much before SATA III arrives.
One downside is that they do wear out - probably sooner than a conventional drive. The cells can only be erased and rewritten a limited number of times. I've seen figures of 10000 to 100000 times mentioned. This may not matter for a system or root disk, but it's not hard to imagine that some usage patterns may be an issue. One that comes to mind is logging real time tick data to a database where each tick causes an erase/rewrite cycle to the disk "block".
There are (more expensive) enterprise class SSDs that use SLC technology that are supposed to be much more durable than the MLC retail products.