I would still use a VP180 with the M60s. As mentioned, the VP150 sounded thin. The other problem that I had was for some concerts where the bass guitar comes mostly from the center, it was very weak. It is just a better speaker overall if you can accomodate the size. I had both at the same time in my house and for me, it was worth the extra $300, for others, it might not.
"The problem is choice..."