The best PD ?

[Samhain]

EA Abysia has exceptional PD. Though the complete lack of missile troops proves a critical weakness as the game progresses.

As for monkey PD, even unsupported it can be useful against the right opponent. I saw it rapidly dismantle 8 earth elementals with surprisingly few losses.

[rabelais]

LA TC for vanilla. CBM the new machaka is quite good.

[AfroSquirrel]

Fata Morgana seems to make for some nice PD to me, though my experience is very limited. 30 Phantasmal Warriors may be very short-lived chaff, but since they're Phantasmal Warriors they contribute virtually nothing to the "75% HP lost = auto-route" mechanic.