Jon, it is well worth the rental; however, Wal-Mart started carrying the DVD for only $5.88 recently. Yes, that's right, under six dollars. I'd pick it up even if you didn't have a DVD player since it is a real good reference for building a T-55 tank variant. The movie has a lot of guys that you'll recognize from TV or other movies but won't know their names right off (the Egyptian guy from the Mummy, one of the Baldwin brothers).
Good flick, interestingly they use US tank commands when operating the tank and the tank starts off with a 5 man crew, but the T-55 is a 4 man tank. Seems like there is a lot more space inside the turret than would be in a real tank. I'm also not certain of how the escape hatch works in a T-55, or if it even has one, but in the movie they use it like regular hatch.