I'm no expert on the matter. (Just going to get my first SSD.)
But, it clearly says on the Anandtech SanDisk Extreme II review, that it is their current favourite.
They also state in the Samsung 840 and EVO reviews that they are using 3 bits per cell, instead of the usual 2 bits per cell. This seems to be a factor that might affect the lifetime of the Samsung drives. They do still state that the 3 bit per cell seems to be reliable, but I'm a bit hesitant, because I want reliability more than extreme speed...
That's why I'll personally probably go for the SanDisk Extreme II as per Anandtech recommendation in their review... I hope it will be reliable and have a long lifetime, and still offer very good speeds.
(Didn't read the reviews very thoroughly though, so I might be wrong. But both of them are probably very good choices.)