Generally myself i've not watched that much in terms of Gundam, however i did watch the entirety of Gundam Wing and Endless Waltz, which, ok weren't the best that Gundam had to offer, but i certainly enjoyed them. I never actually finished Wing until after i finished the first season of FMP, so i did actually find it quite funny how similar both Sousuke and Hiro Yui were to one another, heck i even liked the fact that it was pointed out in Super Robot Taisen W as well, and they both seemed to get along as well. I'm at present trying to look for the series(and movie) cheap so i can watch it again, but money being the way it is with me, i'm not sure as to when i can pick it up.
On other series, i am actually watching Gundam 00 at the moment, only 18 episodes into the first season though. I thought it had a bit of a average start, never felt like anything special, never felt like it was bad either, but it gradually redeemed itself as it went along, and at the moment, can quite safely say i'm enjoying it. I'm aiming to watch a few episodes of it tonight, but it'll depend on how tired i am(having not slept yet, as per usual).
On that note, i do have a bit of interest in G Gundam, i know its the only "Super" mecha series of the lot, so it does make me wonder how different it is, so will ask on if its still worth a good watch.