I can say with a great deal of certainty Apocalypse Frame is my golden mean for mech games.
As a Battletech kid with big love for 08th MS Team there's a special flavor of mech stories that lands with me. Finding a game that balances customizability, the option to explore story outside the cockpit (without going to far in that direction), and tactical depth, while keeping it all manageable, and play session times snappy - felt like an impossible act. But A.Frame does this. It is that balanced thing. Accessible, flexible, deep, and engaging.
Every one of the continual expansions (which I've sampled here and there) brings something novel and necessary to the game - granting you new mechs and campaign options, new opponents and ways to engage with them. Different ways to play if you want them, but nothing to get in your way if you don't need it.
Though it has a built-in, compelling setting, A.Frame is flexible enough to be what you need it to be. Gear and armaments cover all of the classic tropes and mechspectations, so you can translate your titans and mechs and mechas and frames and angels and whatenot in a satisfactory way; should you choose to play outside the native setting.
I really dig this game. Did you need a mech RPG? Yes? Great, this is the one.