Everything sounded much better. It MOST DEFINITELY is worth the extra $300. So don't hesitate about getting it if you're on the fence.
I definitely agree.. the VP150 was never meant to be with the M80. I moved the VP150 with the M60 and it's a perfect match. The VP180 blends nicely with the M80. I checked the output of both M80 and VP180 with a spectrum analyzer and there is a difference. Seems like the M80 go lower and are able to go higher with the same test tone. The lower and higher frequencies were cutoff with the VP180.
It may be related to crossover configurations, my m80 are v2 and VP180 is v3.