The drives I am considering will be my primary and only disc with the exception of a backup velociraptor I might use. This will be for my gaming system.
What I know so far is the Samsung 840 is very fast read speed wise which is my primary concern. It does have slower write speeds though. The Samsung uses TLC NAND which has a lower life expectancy than MLC.
The Mushkin Chronos is not the fastest device on the planet but its price is nice. It uses Synchronous MLC NAND so it does not suffer from the slow downs of un-compressible data like the OCZ agility drives did. It also has a longer life expectancy than the Samsung.