When not a frenzied state of war, I love the small raiders scenarios. Single lances or companies, or maybe at the higher outside combined arms battalions are the stuff of the nitty gritty, every unit matters, lose-that-'Mech-and-you're-screwed mentality that made the initial setting so attractive.
When war is on the horizon, or already here, bring on the regiments. In fact, bring on more than that. I want to see aerospace fighters jockeying for the kill, I want to see a full battalion of 'Mechs leveling a city block on their march of conquest. I want to see a pair of regiments and then some pitting and scarring the countryside with stray blasts of energetic death and divots torn out of armor to the tune of the rippling staccato of more autocannons than you can count. I want a doomed ASF plunging into the middle of a storm of missiles that weren't even meant for it in a last ditch effort to mean something on a battlefield the size of an entire planet.
That's what I like. O0