Not a Sleeve guy, but the one thing that I would say is that the Sleeve is the new kid on the block, in that it has only been in the last 13-14 years as a stand alone proceedure.
The jury is still out as to long term results. With any of these proceedures you can still gain weight if you get away from eating right.
I can tell you that after I did all of my research I did go with the RNY, and here are some of the reasons why I did.
1. It has been the Gold Standard for years
2. There is more long term studies / research
3. No cheating, persay but it will let me know that I shouldn't have ate something after the fact (I won't try it again anytime soon........lol )
4. I was able to keep all parts
5. My Doctor told me that in the event there were major problems it could be reversed (some will argue no but that's what mine told me)
Those were just a few of the reasons I went with the RNY.