I want to add a DSS to my 27" inch. Was about to order a Crucial M4 512GB and contacted a local Apple Authorized Service center to put it in. I am confident I could do it, but rather they do it to avoid warranty arguments. The would charge me $150 to come to my house and do this.
But I decided to wait until I see what Apple comes out with on their DSS and see more reports of the various DSS units - many appear to have issues such as the right cable, the fans, the beach-ball, new firmwares that have no Mac updater, etc.
It is running fast enough on the 2TB and I do not boot that often (stays on all the time). But I have the factory DSS 512GB on my MacBook Pro 2011 and absolutely love the performance, supported TRIM and no issues whatsoever, even though it is not the DSS with the highest specs.