Hey Chris,
My experience is with the M60s but based on previous posts the difference between the 60s and the 80s is in their power handling ability. You can find previous posts from Ian where he states that the 60s and the 80s are very similar in sound reproduction. I for one am extremely pleased with my 60s and if you read some of the reviews on the 60s and 80s posted by Axiom consumers I think you will find it very helpful.See if you can find the review posted by Chesseroo on the 60s, it's very informative.
I have auditioned the PSBs and in my opinion you are better served with the 80s or 60s and you have nothing to lose given the 30 day return policy. My only concern is your source, you may want to upgrade it if you decide on the 80s.
Good Luck,
CAV104
