Hero Awesome is the best assault. Good mix of weapons, heavy armor, and 80 tons running around at 82kph. Ridiculous. Although I prefer my lights and mediums, personally. I'd rather give myself brain surgery than trundle around in an Annihilator at the speed of nothing.
The PB? It's just 68.8kph. I prefer the 9M, just slightly slower with 64.8kph, but with both Mechs having XL engines, that's 4.5tons of extra loadout. I also think the hardpoints are better, at least for my playstyle. The one problem is that it starts to show up late in the game.
Ok now I got all flavours of 100 ton mechs. Which one is your favorite? Atlas? KC? Annihilator?
The AS7-K is my favorite of the 100tonners. Move 3, XL engine without the "negative side(torso)effects", 2 large energy, 1 large ballistic and 1 large missile hardpoint, AMS... and 2 med energy to round it up. Lots of potential firepower, can be build for long range or mixed range, I love those. At least for my AI pilots. For myself, I prefer the hero KGC with 4 large energy hardpoints. Put on some decent large lasers, send your pawns in to soak up damage, stay back and headshot everything.
You have to take care though, if you get shot at too much, you either end up getting cored or losing your weapons. Or both. The CT hitbox seems to be really, really big. So are the arms.The Atlas seems to be much sturdier.
But I still prefer my trusted Mauler-1R over all the 100tonners. 2ERLLs, 2 LRM20-ST with artemis, 4 MGs. You can snipe aircrafts from beyond sensor range or cut out cockpits, also spam missiles at everything. Having 4 MGs adds plenty of heat-neutral firepower for the occasional brawl.