RAID 0 Samsung 840s


As far as I'm aware the 840 is just as reliable as the 840 Pro. It's less durable, but that's something entirely different.

As for the question, I'd recommend a 250 GB Samsung 840 over two 120 GB Samsung 840s. It's still faster, though not twice as fast, but it's significantly cheaper per GB.
 


Quite simply, no. It looks great on paper, but realistically, you will never make use of all the bandwidth of a single drive, and raiding them will only serve to slightly hinder the greatest thing an ssd offers, ridiculously low latencies.