Your surgeon is right it is your decision, but, your surgeon also knows based on past patients experience and your health background, stats etc., what she feels based on her experience what would be the best for you. The surgery itself, the aftercare and long term outcome.
I've never had to throw up, get the runs or any issues with my bypass. I feel most ppl don't have issues, but you hear about these that do, because why post everything is great I have no issues or questions?
I chose the bypass because I have the worst luck known to mankind and I just knew I'd start getting acid refux/GERD if I didn't and I'd be back for a revision later. I've had no issues - none!
I'm not sure why you think getting a SADI wouldn't have a chance to effect you the same way a standard bypass would. There is still the possibility of nausea/vomiting etc. I think if you only have 100 lbs to lose ....I agree with your surgeon, it might be a bit much unless you have diabetes or a BMI of 50% or higher.
Just my two cents..although with todays economy..maybe its only worth a half cent! Finally, you won't spend your entire life only eating a spoonful of food at each meal, just smaller portions.