First let me say that the Vise website does not do a very good job of explaining the product - specifically lacks informing you of what the different numbers/colors represent. Through reading the forum, I've figured it out based on some of the users' explanations.
Having said that, I have been using the gray version for several years based on borrowing some from a friend and it being available in the local pro shop.
There are some pluses and minuses to using the tape:
Plus - goes on your thumb, which is quicker and easier than using traditional tape in the thumb hole.
Plus - Works pretty well and is flexible.
Minus - If you sweat, you will have some problems keeping it on your thumb. It tends to wrinkle, bunch up, and come off at the edges, much like a band aid.
Minus - Leaves a sticky residue on your thumb, which is a pain in the rear to get off.
Minus - cost. It's more expensive than bowlers tape.