I first looked into WLS about 15 years ago. At that time, gastric bypass was the only option from most surgeons, and I was scared away (and talked out of it by my family) due to the potential complications. It was mostly being done as an open procedure; the surgeon I talked to was doing it laparoscopically only for patients with a BMI below 40. When I started looking into it again this year, I was leaning toward the gastric sleeve because it seemed like a less extreme, less scary version of WLS. But when I went to my consultation with the surgeon, he pushed me toward gastric bypass, mainly because I started with a very high BMI (60) and gastric bypass tends to result in slightly more weight loss.
The more I have looked into it, the more I became convinced that gastric bypass was the way to go. Maybe it was just confirmation bias since that's what the surgeon thought I should do, but I learned that the complications are actually not that different between sleeve and bypass. They are both done laparoscopically and have relatively quick recoveries. You have to take vitamins either way. Dumping is more common with bypass, but could happen with either. I have never had acid reflux, so I wasn't too concerned about that, but I have seen a lot of people on this forum end up with GERD after having the sleeve, and a lot of people getting revisions from sleeve to bypass. I saw a surgeon on YouTube (Dr. Vuong) say that everyone should get the sleeve because you can always get it revised to bypass if necessary, but to me that's crazy -- I don't want to go through a second surgery! I'm 3.5 weeks out from bypass so the jury's still out on whether it was a good decision, but that was my decision process.