Super Robot Wars OGs 2: Played through. A lot of fun! Played on EX Hard, as my roommate beat the game before me. Got about 52 skill points. Wasn't trying for them all, just enough to get the final level.
Granzon was my top ace, with nearly 200 kills. He's clearly the strongest unit in the game - even on EX hard with no upgrades he's practically invincible.
Second top ace was... Ryoto, in the Armorlion, with 180 kills. He was also one of my best units, and he joins very early. The strongest twin I had for the whole game was Yuuki (Main) (Rathgrith Raven) and Ryoto (Sub) (Armorlion)
I think the Rathgrith Raven is the single most useful mech in the game. It got me basically every skill point in the EX portion of the game with Yuuki's twin spirit, it's as durable as a Grungust, but very dodgy. It's got a lot of power against everything but bosses... But that's why you have your other 30 units. And he joins incredibly early. Sure, mechs like Exexbein or Geant Chevalier (probably the #2 and #3 strongest mechs that I found) are better, but him and Ryoto were useful the whole game - I had them cover the entire left side in the final level! And I wouldn't dare send mechs like Aussenseiter, Vysaga, or Compatible Kaiser anywhere near those guys, or they'd get torn apart.
Anyway, the game was fun. Honestly, with a few exceptions (Guests, lategame plane enemies) the grunts were actually pretty tame. And your guys get way more accurate as you go on, which kind of surprised me considering earlygame hit rates. SP was also never a concern outside of a couple of lategame levels (The last Earth Route split level was tough, as I wasn't expecting the Air Christmas to show up, and I had blown all my SP earlier.)
Still, it was a lot of fun. And the last boss was tough, hitting half my guys with his spirit lock, including both people that have the cure status spirit, leaving half my guys unable to attack for the first turn.