I don't own the c300, but I've been doing a lot of research as to what drive to buy. The c300 is only worth it if you're using sata 6g, otherwise probably a vertex 2.
Theres some complaints about marvel sata 3 ports bottle necking the drive. Not sure if this is a widespread issue or not. But you might want to look into it.
The vertex 3 is supposed to retail for 250-270, but retailers are price gouging at the moment to prices upwards of 320. I have read of people snagging them for the MSRP though.
If it's not a rush I'd wait to grab a vertex 3 for closer to its msrp.
Edited by Raxus - 4/12/11 at 3:34pm