There isn’t one tank in that bracket that I am a fan of.
Rank 6:
XM-800T and the XM246. The XM-800T is pure cancer and can just decimate/pester/piss off most enemy. It’s fast, has a quick firing gun which is stabilized, and has scouting ability/spotting drone.
The XM246 is not as fast as the Gaypards, but it’s the same gun platform and has a large empty space that can absorb punishment.
The M60s series I find are nothing special. I find the T92 and M56 suit my playstyle, but that’s just me.