Pretty much what Blaze said. There are relatively few 3.5 inch SSDs out there, and none currently from Intel. I'm just going in at the entry level for now with a 40GB drive (the X25-V), to see what kinds of things will benefit from the drive. While not the quickest in terms of large file read/write, it does offer excellent 4k speeds for the price, and some of my workload could benefit from that.