If you're willing to trust me to condense a dozen or so reviews:
The C300 is one of the good all-around drives. The sequential read speed is better than most, but doesn't match the m4 or upcoming Vertex 3. The random 4K read speed is some of the best you'll find, but not overwhelmingly so. It's got really good read/write access times (even for an SSD), but this is due to lazier-than-normal garbage collection, so it should really be used on a TRIM-aware OS (ie: Don't use it with XP... also: Stop using XP). Its a SATA-6Gb drive, but it doesn't reach so far over the 3Gb limit that you'll feel like you're crippling it by putting it on a SATA-3Gb connector. They're some of the more reliable drives, though they aren't quite as reliable as Intel, and since Crucial/Micron makes the NAND you can be fairly sure they're not getting lower-quality binned chips from someone else. They seem to be slightly more reliable than the bulk of the Sandforce drives, but not so much that you'd really care. The only real down side here is that the drive is being discontinued and replaced by the m4/C400.
That's a whole bunch of text to say: It's a decent drive, and fast enough that most users aren't going to notice a difference with a faster one.