not everyone dumps (the stats I read here and elsewhere are that 30% of RNYers dump. I don't know if there's any hardcore research behind that, but suffice it to say, lots of us don't dump). So I wouldn't necessarily use that as a reason to go with RNY, since many of us don't have much trouble with sweets (unfortunately....).
I went with RNY because I had GERD, so it was a no-brainer. But the other thing I liked about it was that it is a much older surgery (although techniques have changed and improved over the years) with a lot of long-term data behind it.
you have to take vitamins with both surgeries (although more with RNY), but it becomes automatic after awhile. I don't even think about it. I take a small handful at breakfast, a couple at dinner, another calcium sometime during the day, and iron before I go to bed. Deficiencies are pretty rare as long as you keep on top of your vitamins.
they're both good surgeries and people have had great success with both. I don't think you can really go wrong either way.