Alright, I'm going to give you a brief impression of each Gundam movie / show that I've seen:
0079: If you can get past the dated animation, you'll find one of the greatest coming of age stories ever told. Fantastic cast, wonderful setting. Cool mech designs and music. TV or Movies, you can't go wrong. My recommendation would be to get to Episode 29 of the series and then switch to Encounters in Space, as the third movie adds quite a bit.
Zeta: Weird first 5 episodes, but it settles into one of the best shows in the franchise. Very stylish and cool. Iconic
ZZ: I don't mind the slapstick first half, but it is a weird turn. Second half is better.
Char's Counterattack: One of the greatest movies ever made.
0080: A must watch. It's a christmas tradition for me.
F91: It's a mess, but I enjoy it. First 30 minutes are perfect, then it falls apart sort of. Looks great though
0083: It's gorgeous, but kinda drags in the middle. There is a very dumb plot twist towards the end, but it's pretty good over all. GP02 is a beast.
Victory: Controversial. I enjoy Uso and his suffering a lot though. He's one of the best pilots in the franchise.
G Gundam: The dumbest fucking show in the franchise and I love it for it. It doesn't take itself seriously, and it's a blast for it.
Wing: Eh. It's popular in the West for being the first Gundam to break big here. I don't think it's very good though. A lot of rehashing ideas much better handled in UC. And the unique stuff isn't great. Fujoshi bait.
X: Kind of boring, and I don't love the character designs. Wonderful OP though. It's sort of mid
Turn A: Underrated masterpiece. Some say the first 10 episodes are slow, but I love it. Very confident series.
08th MS Team: I'm not a fan, though most love it. The Romeo and Juliet plot ruined it for me. Some cool grunt battles though.
Seed: Rehash done worse. Bad character designs. Stupid plot stupid characters
Seed Destiny: First 10 episodes are better then Seed, but then it nose dives into utter bullshit. It becomes even stupider than Seed. Trash
Igloo: Trash
Igloo: Utter Trash
00: An interesting post - 9/11 take on Gundam. Goes weird places, but is sort of like a better version of G-Wing
Unicorn: Brilliant until the very end, then it sort of flounders due to its reveal, which was kinda dumb. Still top notch celebration of UC.
Gundam Age: More boring than anything. Multi-generational gimmick is kinda cool, but doesn't take advantage of it. Is basically a promo for a game that wasn't released in English.
G-reco: i wanted to like this really bad. But ts sort of confusing. I still cant tell you what the plot is.
The Origin: Fantastic prequel to the original series. Makes me want a remake of 0079 so bad. Some of the elements added are silly though.
Ironblooded Orphans: Very cool ending. Kinda of boring otherwise
Island of Cucuruz Doan Island: A weird movie. It is a remake of a throw away episode of the original, not sure why they made it. It looks nice but isn't necessary at all.
Hathaway: Probably the most mature of the franchise. It's sort of slow paced and focuses on a love triangle, but it's handled tastefully. Plus there is a cool battle sequence in the back half.
Build Fighters: Fantastic show
Build Fighters TRY: Bad show.
The Witch from Mercury: I did not like this at all. Its popular with new people though, so maybe its just me. But it felt week to me