Way I see it, it's a franchise anyone can get into because everyone had a starter series. It has political intrigue in most of them, much akin to Five Star Stories and it's the opposite of Macross.  I can say that much of the earlier ones like OYW, Z, 08MS Team, Stardust Memory, Wing, Turn A, UC and SEED has the most political intrigue you'll ever find in the series.  Not into that? You got War in the Pocket, G, Build Fighters, Witch, and throw in the manga if you find some. It's okay if you add Compati Hero in there.  Hell, I'm rather I'm into SRW since it does tie up some loose parts that never got explained or just most if not all of the franchise a breather from being always serious.  I mean I grew up on mecha so I was gonna reach Gundam eventually, I grew up on Golion, Macross, Bismarck, and Tekkaman Blade which I suppose is a blessing because not many people don't know that much as far as mecha goes.