I have tried the White, the Black and the Red Tenga Flip holes, plus several Fleshlights.
My complaint is the Fleshlights have far too much of the "interesting" texture deep in the sleeve. The stuff near the opening is not very interesting and that means if you're not very long you won't get much out of it.
The White (original one) is the only Tenga Flip Hole that I actually enjoy, and I like it better than all of the Fleshlights. And it's pretty much just for one reason - there is a nice round "orb" which they call a "Click Orb" or something silly like that on one side just inside the opening. It looks like a single breast. That little round nub is the right size and texture to have rubbing on the underside of my penis and it feels a lot like a very good tongue.
For me, all the tiny little waves and ripples in all of these masturbators are largely wasted effort. They are too small and numerous to notice, and the only thing they do is provide spots for lube to hide and messes for you to clean up later.
So go for the Tenga Flip Hole White (original). They had a great design and I think they really haven't done a good job with the subsequent designs.