Busta Bloodnut

Hello all. I've been reading thru this and was wondering what are more pros and cons of getting this for my Alienware m18x R2? The adapter? Also was wondering if that veloceraptor adapter is the only one that works for the m18x? Ive seen other kinds of ones on eBay for way cheaper, but I don't know enough about these to know better. I mean I would assume that a Samsung 990 pro would be way better than the 840 evo msata I have in there already.