Ok, just picked up my QS-8s.

SO now I basically have the Epic Grand Master: M22s + Atlantis stands, EP-175, QS-8s...but no VP-100. I have vp-50 my friend sold me for $100.00 CDN

Is it worth upgrading, and if so, is there benefit to going to the VP-150 instead of the 100, or does the 100 match the M22s better?

I'm using a relatively budget Harman Kardon AVR-120 (45 watts RMS per channel)

There are two reasons to consider upgrading your center channel:

1. You hear tonal shifts that bother you.
2. The VP50 can't fill the room adequately, and the receiver clips when you turn the volume loud enough.

If you're otherwise happy, don't bother. Though its specs say it's a sensitive speaker, the VP150 is starved for current, and you might find yourself needing to pick up a separate amp with your modest receiver.

It mostly seems a little small compared to the M22s and the QS-8s.

What about the VP-100 as a compromise?

Either stick with what you have or do the 150. If you do the 100 you are going to be wondering how much better the 150 would sound and be in the same spot in a couple of months. Upgraditis strikes again!

Hey, don't impose your lack of willpower on others...

I have a VP-100 and I'm perfectly happy with it. I know the VP-150 is a better speaker, but I don't notice any flaws in my VP-100, so why upgrade?

I just figure if he is already ready to upgrade from the 50, well....you get the idea.