I own 3 different set of windows. All of them are tinted, otherwise they look stupid.
The Viper Mania windows look awesome, and the slider window is good for getting some air, but who needs that when you have A/C. The main use for this slider window is so that you can reach in, grab the door handle and open your door. It is too small of a window so your arm will not fit out of it. It pops in and out in seconds with no screws or bolts needed. We once left a night club and there was a taco shop right there that we wanted to drive through, but with the top on and the windows on, you can't go through the drive through without opening your door to get the stuff, and it was too narrow for that. So just before we went in, I opened the door, popped the window out and handed it to my passenger. Took all of 5 seconds, and all of about 7 seconds to put back in after we were done.
I have the AutoForm window which is very similar to the Viper Mania window, except the sliding window portion opens up over 1/3 of your side window --actually, almost half the window, so you can literally go through a drive through and pull food in through your hard windows -- cool! It also has a locking feature, so that people can't get into your car by sliding the window and opening the door. This one requires you to screw in a bolt at the top. It has the tightest fit with the least amount of air hissing (leaks) in the cabin.
I have the Snake oyl curved windows -- these are the only windows I will put on the car when I drive with the top off. They look cool in my opinion and reduce wind hammering by a LOT. WHen I drove up to Las Vegas (5 hours) I had the top off and these windows in and wind levels in the cockpit were minimal -- we were listening to a comedy CD on the way up there, to give you an indication.
So, in all, I think I like the looks of the Viper Mania window the best with the top on, the Snake Oyl for sure with the top off, and if I am going somewhere where I want to secure my car by having it locked, then the Autoform windows are best.
I will try to take photos of all three this weekend so you can see what I am talking about.
Manny