Of course the other great tactic for Mansions is Ayephones. Holding alt after scanning with one, now shows the location of the blips in the battle map itself. You still don't know for sure which floor they are on, but it can still be a big help. As you get toward the end of the mission and more of the mooks are panicking, its likely that they will freeze in place so the ayephone isn't fool proof.
Also great is the Novice outfit, as you have 3 sense so you can spot the enemy and ID them through other floors. I like to have 3-4 of these, and base a 3 man team around them.
A couple other pointers: Always do them during the day. Night mansions are worse. Just don't.
Factions: Academy, Church, Guild. Academy is the worst because they will spawn with a few drone units that can't surrender. Everyone else on the whole map may have panicked or berserked, but until you find and eliminate that last drone you are stuck. I think early Academy is the only faction I might be tempted to bail on. The other factions are all manageable.