Most Realistic Gundam Yet.
The 08th MS team is by far the most realistic Gundam series yet. You have the series' Humongous Mecha disabled by things like sand, the antagonistic Zeon forces painted in lighter shades of grey, the casts' own Earth Federation showing off their darker side, and best of all, A cast composed of regular grunts. No fancy-pants newtypes or aces here, just a regular group of troopers with giant robots.
The plot is well thought out, and revolves around the type of events that could conceivably occur in a Mech War. In place of the almost standard 'Hero vs. The Universe' style present in Gundam, the team has to work together to take out even small groups of enemy forces. In fact, the characters have been shown using up entire clips to destroy a single Zaku, the epitome of Gundam cannon fodder. Also, while holding onto a giant super weapon as a major plot device, the missions aren't of extreme importance. They range from patrols to securing supply routes for most of the episodes. That is, of course, up until the final episodes where a Zeon-held city is attacked. Overall, this series really captures the feel of what a Gundam war would be like in the trenches, in place of from the Elite Special Forces' point of view.
Another thing about this series is it's characters. Being a Zeon fan myself, I typically wish the main characters would just take the laser/bullet/random instrument of death and die peacefully. In this one, the characters have enough flaws so as to not appear goody-two-shoes heroes, but real people. The same goes for the Zeon characters, who managed to reach levels of awesome not typically achieved by normal humans in the series. However, there are still the a few stereotypical evil-doers, but they're the ones you want to die spectacularly anyways.
In closing, if you want to watch a Gundam series, this one is the way to go.