Sorry for the long post, but you have a momentous decision to make. There is no ideal bariatric surgery for every patient. Some people should not have the DS, such as if they are unwilling to follow a rigorous daily supplement program, go to annual follow ups with extensive testing regardless of their insurance, and eat what they should, before they eat what the want. Other people have different goals, such as they would be fine with a 50 pound weight loss out of 100 pounds overweight or okay with some better loss early on, with a higher chance for regain in the future.
I cannot recommend the RNY, with the risks of regain, reflux, vomiting, and dumping, as well as the lifetime limits on food. Micronutrient deficits and bowel symptoms also occur with the RNY for some people, so thats not a good argument for it. Revisions are much more common with RNY than with DS. Wasn't willing to live like that. A lot of other people are. Since RNY and lap band were the only choices when I was looking, and I knew people who had failed with both, I would not have had surgery without the DS. My reasons for DS were long-term success, lack of hunger controlling my life, diabetes and high cholesterol reversal, and the ability to eat normally, just less quantity and more protein. It's worked out well.
I think the lack of data with SIPS is a matter of concern, and you are young to have a procedure with unknown 20-year outcomes. The chance for micronutrient deficits would seem to be lower with SIPS over DS but that is still theoretical. The chance for long term weight gain would seem to be higher with SIPS, but that is also theoretical. The chance for less diarrhea or flatulence would seem to be better, but many people with DS don't have these problems and it is unknown how many SIPS patients will have or not have these problems. If you have obesity-related diseases, I would want to be assured there was a good chance they would be resolved with SIPS.
I would certainly get a second opinion about this, because you may get different asessments of risks and benefits. Congratulations for rejecting sleeve gastrectomy and the horrible lap band. I think only you can decide what's right for you, given your goals, your age, and your tolerance for risk. I'm glad you are investigating. Think twice, cut once!