Glass top tanks?

I am looking to buy a blue tongue skink soon, so I am looking at my options for tanks. I know that a 40 gallon long tank is best, so I am doing price checks for different places. I went to a small pet store by my house and the guy there said that he doesn't have any reptile things in stock, but he can order a glass top 40 gallon long tank, with lights, for $150. I have never heard of a glass top tank. Any advice on them? Am I better off with a screen top? I didn't think to ask him this, but maybe someone here knows the answer: How does the lighting work? Are there cut outs for them.. If not, wouldn't the lights heat the glass too much? Or the tank not enough?

You need a screen top or your going to have to mount the lights inside the enclosure,uvb rays do not pass through glass.

Ya, I actually just got done reading that when I was doing some more research on lighting and whatnot. I still have sooooo much to learn before I get my BTS, lol. But I definitley want to get all my research done NOW not one he/she is here and I've screwed something up. Thanks :)