I never thought I'd get into mecha anime. Now I'm probably one of the bigger fans of the genre on the board.
I like robots, machines and mechanical things in general and that side of things always appealed to me, but I never really liked the idea of child protagonists and combat being a major focus of the show "Shonen Fighting Anime #912, episode 7480" is still something I can't get into. I don't particularly find fights interesting unless they're really, really well done and there are actual stakes.
Patlabor helped ease me into the genre though an actually interesting cast of adult characters and a creative team I knew and trusted (Oshii, Itō and Takada specifically). Unfortunately it did kind of spoil me because it's still the best mecha franchise that exists as of today, imo. Even if you don't think you'd like mecha anime, Patlabor is definitely worth a try because its characters and their interactions are some of the best written in pretty much all anime for my money.
The second franchise that became very dear to me is Gundam's Universal Century timeline. As another classic, it seemed like a logical place to go from Patlabor. I certainly won't deny these shows have their problems, mainly with repeating plots and overuse of the same character archetypes, but taken as a whole it's a grand universe of interesting characters, technology and themes probably at least the equal of Star Wars, if I'm honest. And I say that as a big SW fan. The plot lines run the gamut from goofy to soul-crushing, but partly that's what makes me enjoy it. Because life is like that. The protagonists genuinely surprised me by being a lot more interesting than I expected as well - Yes, sometimes they can be mopey or violent little sh*ts but there's actually nothing wrong with having flawed main characters, it's a lot better than having perfect ones.
While we're discussing the genre in more general terms, something I've felt for a while now is kind of a gap in the market is giant robots that actually posses some kind of artificial intelligence or sentience of their own. You have machines controlled by pilots or bio-mechanical ones which are little more than beasts, but no-one's ever thought to create a show where the robots are at least partially in control of themselves (which is, I think, where warfare in the real world is heading). I don't know if this is maybe a reaction against things like Transformers, the idea that perhaps robots which appear "alive" is more something for kids, but I'd be interested to see the adventures of a self-aware war machine.
Aldnoah Zero is prompting such stark divisions between posters here I'm almost tempted to try it just so I can take sides and have a debate.