Stamina Unit has bumps all around. It's very intense in the feedback it gives, meaning more sensory input. Some of the
FleshLight models have very modest bumps, ridged and what not.
So, using a "normal" (so many models)
FleshLight isn't totally worthless, some are just less intense.
If you're looking to overcome premature ejaculation, then the
STU would be a good choice I think. But remember, sex, with yourself or with someone else, starts in your mind.
Relax, remember to breathe. And remember your kegel exercises! Kegels mean a lot for
stamina.