is Gundam collectively as a show any good?
"Collectively" Gundam is not "a show." Gundam is a property associated with a lot of shows that are not really linked together by anything except a popular line of model kits and toys. :) At the top-most level you've got your division between "Universal Century" and "Alternate(?) Century." UC shows include the original TV series and all the other shows and OVAs that are direct sequels to it. AC shows are all unrelated to anything, the only similarity is that the hero mecha share similar heads (even the made up technology is different). Gundam SEED is the only exception, it has a direct followup series currently running. UC shows are all linked together by certain characters and events, but thematically they are all quite different and while fans are generally split into two camps (UC-elitists and everybody else--UC is the SegaSonic of Gundam) even in the UC line, liking one show does not mean you will like the others. AC in particular tends to be trendier and tries out different things--G Gundam is a kung fu robot "fight of the day" show, Gundam Wing is a bishonen political drama, G-Savior is a movie filmed in Canada, etc. The latest, Gundam SEED, is a "reinvention" of the original series combined with the shinier mecha and prettier boys that made Gundam Wing a success, and it's worked very well to that end. A lot of UC elitist-types hate it, and not everyone is going to like it, but it is a pretty good show that deserves its popularity in my opinion.
The UC series does hold together somewhat coherantly, and is characterized by consistant (and advancing) technology, but always tries to stay somewhat grounded in vague sci-fi realism. It's not the most realistic mech show out there of course, but it is fairly "smart," treating the subject matter as realistically as possible if you accept the fact that for whatever reasons giant space robots are feasible weapons. In a UC show, Gundam is a prototype machine given performance above the previous generation (and typically the production versions as well) but is not invincible (though combined with something ridiculous like "Newtype" pilots and they pretty much are anyway). At any rate, it's (typically) nothing like Wing or SEED, the battles are usually on a smaller scale and do not involve a single machine destroying entire armies of fodder mecha.
Typically.
You don't need to know any background from any other Gundams to enjoy 08th MS Team, though it does put the war into some context that will be appreciated by fans of the original TV series. There's no need to consider Gundam as a whole.
I also recomend
Gundam 0080: War in the Pocket, another OVA (set in the UC timeline) with little connection to anything else. It's a different take on the mecha theme, and still takes itself fairly seriously (and intelligently) despite being pretty light-hearted at times.
Getting away from Gundam,
Macross Plus is THE Macross to watch if you want a good mecha anime--the story is basically "Top Gun with transforming planes" and is really, really good. My anime club would show it every now and then and people would walk in from the hallways to check it out. People who "do not like anime" like Macross Plus--it's like Miyazaki or Lupin the 3rd. I consider
FLCL to be a mecha anime, and it's must see whether you agree with me or not.
Dai-Guard is an often-overlooked anime about an insurance company that uses a giant robot to prevent disasters (so it doesn't have to pay insurance claims) and while pretty silly at times ("Even a salaryman can protect the peace!") and decidedly "monster of the day" anime (a lot of Eva influence in the enemies as well), it's well-done and fairly smart. There's also the ever-lovable
The Big O, mixing cheesey robot design with Batman: the Animated Series-inspired scenereo, which is a winning combination in my book. On a similar note, there's also
Giant Robo, a vaguely "retro" robot anime (primarily in its character and mecha designs) that is considered by many to be a modern classic, but it also takes itself too seriously. I still like it though.
My current favorite is
Overman King Gainer, a show featuring a robot with mechanical dreadlocks than enable it to fly around. I'm not even kidding. It's a charming show from the creator of the original Gundam. If you liked Eva, you can take a look at
RahXephon or
Sokkyuu no Fafnir--calling them Eva ripoffs is not something anyone who actually enjoyed any of those series would do, but the influence is very obvious. On the other hand,
Dual! IS an Eva-ripoff, minus the angst and considerably lighter-hearted. The Eva influence is so significant that it borders on parody, but not quite.
Vandread is quite likable if only for its overwhelming cast of female characters. The second season is much better than the first, but it's better to be seen as a whole. Finally, I think everyone likes
Martian Successor Nadesico. I seem to remember thinking the overall story arc got a bit stupid, but the individual episodes and great characters are the show's strong point.
I don't think it's out over here yet, but
Godannar is hands down the most over-the-top mecha anime I've ever seen. The sexual symbolism in the first episode alone makes it a must see--it's absolutely hilarious. After the first episode it has already burnt out most of its impact, but it's still fairly entertaining.
Anyway, if you are looking for mecha anime, follow up on any of those that seem interesting (reviews should not be hard to come by) and check 'em out. These all have plenty of robot action (Vandread may be a little weak in that regard, actually..) and I think "intelligent plot" is a bit too subjective, but I'm sure you'll find something you'll like.