It's alright I guess. Not terrible or anything. I'd recommend you join via the server browser menu and search for mvm_ maps, then spec for a bit and mash join red team.

Spy, Sniper, and Scout seem kind of useless because of their inability to spam. Pyro requires that you have a Medic or at least play it safe until you get health regen/health recovery upgrades. Demo is good (obviously) but upgrades for Demo are expensive if you wanna get some good stuff (etc Sticky Reload + Damage). Soldier seems kind of limited before upgrades, still good though.

When I finally got into a game, I got ridiculous lag the moment bots spawned.

Then the server decided to shut down after a few waves.