When the VP180 was first discussed I raised the lobing question, but after looking at the speaker arrangement (frequency range covered vs separation of the pair handling those frequencies) my impression was that the VP180 design (particularly putting the mids side by side) would go a long way to controlling lobing.
You can hear variations in sound with a VP100 when moving from side to side, but so far I have only really experienced that with test tones (where it's pretty obvious) and a couple of songs during guitar solos where the sound was pretty close to a test tone.
IMO having both VP160 and VP180 designs available is great. It would be impractical to implement a W T/M W layout with M80 speaker complement (the speaker would be more or less square) but was practical for M60 complement.
If VP160 and 180 had come out at the same time I probably would have gone with VP160, but mostly because I had been whining for Axiom to make an M60-sized center for so long and the idea of an M80-sized center channel had never occurred to me
