8 years out....

You'd know if the stitches were leaking because surgeons test for leaks, either during the operation before sewing you back up using special dye or the following day by doing an upper GI x-ray.  If you don't have a leak then, it's unlikely you'd develop one later.  It's possible to develop one over the next couple of days, and you'd know because you'd get very sick very quickly, but that's rare.  Ask your surgeon how many patients he or she has had that happen to.  Once the stomach heals, it's not going to suddenly start leaking one day down the road.

Long-term, you're more likely to have complications that require a second surgery with the band than with the sleeve.

It's definitely a big deal. The band causes a lot of damage that you might not realize you have until it's too late. Once a band slips once, it's a lot more likely to slip again. The more surgeries you have, the more scar tissue you end up with. Research about scar tissue and adhesions and the accompanying issues before making a final decision.