Well, obviously I have played them, being I co wrote them!
NucRen is a very detailed game, theres loads of freedom. Vehciles are very musch a big part of the game, and controlling them is really very intergrated. The other guy who wrote the rules is a very amazing sword fighter in real life, so the rules really try to reflect a more realistic take on combat. However, because of this the version on the site is very maths heavy, which is its weakness.
Im actually working on a new set of rules. They are less maths based, so speed up the game. Im even at the stage now where we need to get some playtesting done. This second version is much better than the one on the site, so if you are interested I can send you the new one. SOme critisim would be very uesfull.
Basically, the new rules improve the flow of the game, but dont lose any of the detail. The game blances issues with vehicles too. The main good thing about NucRen is that it works really well multi player. We had a four player game with Debakuk from this forum the other day. It was his first game and he picked up the rules in a couple of turns.
PM me if you want the new version. Its still work in progress at the mo, but in a good way! We have all the rule shammered down and now its just about tweaking the balance a bit.
Oh, sorry for the long meandering post, but this is very exciting for me!