Mostly what others have said. Graphics are... acceptable. Lots of mechs. Best customization in mech game since MW:4. Aside from that, it's garbage.
Aside from the generic missions, grindy gameplay loop, and random availability of mechs and weapons, the garbage menu system alone shows you how little the developers cared. Little things like reorganizing your mechs or navigating lists take forever because of the clunky menus and hotkeys that are underfunctional and switch from one screen to the next. There isn't even an icon that shows when a mech has a missing weapon when looking at the hangar screen, you have to individually check each mech.
It's like it was designed by people who have never played a video game with asset management and never asked anyone else to try it before shipping.