I've been using BSP for a while. BSP solves a lot of problems that crop up with combined arms play, from an organizing a game point of view. Running infantry, air, artillery, and vehicles with TW+strat ops+tac ops requires too many books. When questions come up it grinds games to a halt. Further, I play lots of campaign games, and in a campaign the TW rules are crazy deadly to non-mechs, to the point that collecting xp and leveling up your infantry and tank crews is almost impossible, and really demoralizing.
The full TW rules for tanks and such work best in pick up games with force building restrictions to prevent abuse. A pair of tanks with a mech lance is fine for rules complexity for a pickup game for example, and friendly list building restrictions should weed out people running 20 blocks of infantry at the door.
In story campaigns 20 BSP infantry isn't the problem it is compared to TW rules, so I'm much happier running lots of infantry with the BSP to recreate specific narrative battles.