Yes he is extremely fun and easy model to build. In my local hobby spree we pretend quake is a predator tank for my space marine army. Partially becuase we can and partially becuase he only preys on the weak!
Yea I also got the m6 which is at the same br. It has a better gun at teh trade off of worse Armour. My favorite tank is the t64B which I got a month ago. I am working to get the Abrams to see if it’s better.
For Vanguards, you usually have to be active in solving Portability-related issues and probably assist the Vanguard team to get invited into the team, but you should probably ask FishTank for a better answer about it.