I'm not a fan of the Comet, I don't think it's worth the price over the Churchill VII. I'd rather get the Churchill and save the fuel for a Firefly.
Comet is great alone but with emergency war speed and gammons Hammer is just the obvious choice currently. Like church is good for 150 fuel don't get me wrong but Comet is a fast moving hard hitting beast. Threatens Panthers and Tigers will still doing well against infantry. Solos Panzer IVs and other mediums reliably. Vet 1 white phos shell is godly. The only complaints I have with it are buggy things, the new hv projectile model causes it to miss when attacking ground constantly, and both smoke shell and nade ability cancel themselves with no rhyme or reason quite frequently.