If you want to be a steamroller then 2 primaries that are just a notch above others. Thugs and demons. Some say bots are good but honestly that's because the assault bot carries the set and the rest of the minions are underperforming.
Of the secondaries time is also a notch above the others. Yes we can make arguments and builds for others but no other set has everything you need to solo and melt mobs. Capped defense -tohit -dmg heals recharge buffs +dmg and -res. Yeah it doesn't have alot of -regen for AVs but you can easily purchase envenomed daggers to stack with your own -regen.
Demons are best with thermal. You get high resists to pets, aoe heals, and -res and debuffs to melt AVs. But from play testing dark performs amazingly with demons. Demons have innate high resists and dark just has so much debuffs that it's effective +def assuming you get your fearsome stare and darkest night on a majority of the mobs. That layered defense really keeps your pets safe as they stack -res on -res to melt mobs.
So my 2 cents after making tons and tons of MMs thugs/times just feels so strong. My thugs/time has 240% global recharge with the Chrono shift buff. 45% def to melee and 45 to range. My pets are all def capped with extra and they all have the unique IOs so they have 35% resistance too.
Now to the negatives of MMs. It's alot of babysitting. A patch or 2 ago they removed the behavior of your pets moving so when they are threatened or under a dmg patch they still stay put. Now it seems to be reverted and they run to the high hills still which can be really annoying. Another thing is that because the minions are under leveled they are subject to level penalties when fighting +4 enemies. You can circumvent this by fighting incarnate level content because then your supremacy buffs their levels to your max level as well. Just be aware of course that those mobs are generally tougher.