if you have GERD, they'll usually recommend you go with RNY because VSG can make it worse (it does in about 30% of cases, so it doesn't ALWAYS make it worse). If you don't have GERD, then it comes down to personal preference (although there are people who never had GERD before who do develop it after VSG, so there's that - but it's more likely in people who already had it beforehand).
I had GERD so I went with RNY. I didn't want to take the risk of it getting worse, but some people are comfortable with the risk. I've been very happy with my decision and would make the same decision today.
Both are good surgeries and you'll find people who've been very successful with both.
