First, don’t put a lot of time spent wondering how fast it will all happen. Follow directions and make good choices should lead to success either way.
The speed at which you lose weight is probably less about the type of surgery but how closely you follow the recommendations afterward, your current muscle mass, and how much exercise you work in. I know people who have lost weight very quickly and others more slowly with both procedures. Worrying about time too much can depress people and lead them off cours
There are pros and cons to both procedures, but I don’t think you need to worry about which one produces faster results. If you follow the directions from your doctor and commit to a new lifestyle, you will see success in a reasonable amount of time either way.
That’s my 2 cents anyway.