Not sure. I only have the M50tis, but my impression is that the v2/v3s are improved. However, I doubt the character of the speaker has changed, so it would probably be worth waiting for the M50 equivalent center channel to see if it's feasible for you.
I also used to have the M50/VP100/QS4 setup and it worked quite well. Never tried the 50s with a 150 (heck, I think I've only ever HEARD a 150 a few times, and that was with M60s.) That said, I don't feel like my VP100ti keeps up with my M80v2s or my QS8v2s, at least for music, so I've been toying with the idea of a VP150.
