The animation of the original Mobile Suit Gundam has not aged well; neither has the voice acting. Perhaps the worst strike against it, though, is scale. It's tiny. White Base carried three mobile suits; a Musai carried three or later five. A Zeon battleship only had twelve. The most opponents I can recall Amuro engaging at one time is five. Five, and this is the man that practically won the war for the Federation! Zeon supposedly had hundreds of mobile suits, so where the hell were they all?
Later giant robot series, none of them Gundam, operated on slightly larger scales. Then Macross/Robotech came along, and blew everyone else away with animation that really conveyed a sense of these being epic battles, with dozens of fighters and pods in the same frame. MS Gundam's saving grace is Char, who practically carries the whole show through sheer force of personality. Amuro reminds me far too much of Speed from Speed Racer for me to like him. But even Char can't save the show when it's compared to the newer incarnations.
Zeta in some ways reminds me strikingly of Wing, and that is not quite in its favor. At least Wing only touched on the "best damn pilot/killing machine" theme as Flaser puts it, Zeta harped on it, and it was rather annoying. Double Zeta is just...wtf-ness? They completely reversed direction from Zeta, and the jarring transistion is too much for me to get past. I'm probably selling the show short a bit, because of this, but still.
I've never seen F91, and so cannot offer an opinion.
I'd argue Turn A is only tenously a UC Gundam show, but we'll leave that aside with the comment that whosever idea that was, they need to be assassinated. Otherwise I might start ranting.
War in a Pocket gets a case of the warm-and-fuzzies from the Alex, which is probably my favorite Gundam incarnation of all time. Still, I indict it for the same reasons Flaser chose to indict 0083. It's unique in that Zeon is really the protagonist in the show, as well, and in the end the Kampfer goes on a suicide run to knock out the Alex and thus prevent Zeon from nuking the colony.
I haven't seen 0083 in its entirety, only bits and pieces, but my general impression is good. Still, I feel I cannot offer a well thought-out opinion on it, and so will leave it aside.
My favorite, then, would be 08th MS Team. Shiro Amada is a worthy main character, ably supported by an excellent cast of secondaries, and I must disagree with Flaser's assessment of its character development. It has perhaps the best fight sequences of any of the series; surely the battles between the Zaku RD4 and Shiro's Ball-K, or the Ez8 and Gouf Custom, must rank among the best ever seen on a Gundam show; personally, I would rate the latter as the best. 08th MS Team feels like the true descendant of MS Gundam. Their scale is the same. Yet it is vastly better because it is not trying to be an epic story. 08th MS Team is the nitty-gritty of the ground war, down at the squad and platoon levels. Certainly some of them do exceptional things, but not counting Aina and Ginas Saharin, these are not really exceptional people.
And one last point in 08th MS Team's favor, a subtlety but vastly important in my eyes. Whoever designed the fight sequences for it was either given more time, more money, or was simply smarter then the person who designed most of the others: there is a believablity to the way that the mobile suits move that the other shows lack. Mobile suits look human, but they aren't really, and they shouldn't move in a completely human manner. And 08th MS Team's don't. On several occasions they move rather like a marionette with most of its strings cut, because of sudden thruster-based manuvers. And that makes sense, really, since they ought to if they're trying to remain balanced and not pitch over and bury themselves in a building or worse. As another point in the show's favor, they do this only in atmosphere: in space gravity isn't seeking to make your mobile suit fall flat and there's no reason to, so they do not behave this way.