Neither.
There are two other choices you should research as well---the Sleeve/VSG, and the Duodenal Switch/DS. Both leave you with a much smaller yet still fully-functional stomach, not a pouch with a stoma. The Sleeve is a restriction-only surgery like the Band, while the DS also has malabsorption, like the RNY (only permanent.)
Depending on how much weight you have to lose, either of these should be an excellent choice. The DS has the very BEST long-term, maintained weight loss AND resolution or prevention of co-morbs like diabetes and high cholesterol. The DS also has the very most liberal post-op eating plan.
I chose the DS because it offered me the very best hope of losing and keeping off enough weight to be healthy and happy. I knew I'd always need to take NSAIDs (no-nos after either the RNY or the Band), and I didn't want dumping syndrome or any of the other problems associated with having a stoma.
At nearly seven years post-op, I'm effortlessly maintaining my lowest adult weight ever, and eating 2500-3000 tasty calories every day!