The Maus looks like one of the only seven gear heavy tanks worth deploying since it's period of invulnerability is long enough to buy off it's deployment cost. My main problem with high deployment cost tanks is that by the time you're able to field a second tank you've been picked to bits by a half dozen Comets. A seven gear heavy just doesn't hold the line as well as a cheap heavy or defensive medium and a couple arty with Downfall.