RAID for a notebook? One of the twin drive ones?
Get an Intel, don't bother with the others at this point. Too many brands have issues with some and not others and it's no fun tracking down which models are which.
Intel X-25M and be done with it.
I have one in my desktop, one in my laptop, and one in the Pig Truck.
Oh, and for what it's worth, the one in my desktop is about 2-2.5x as fast as the 3x15k Cheetah array with a dedicated that it replaced.