I'm strictly Stereo (2 Channel music - no movies, TV etc).
I don't know if anyone has had a chance to do side-by-side comparisons between HP and standard versions of the same speaker, but for 2 channel music speakers without subs I would be tempted to spring for the HP version. There is a $700 CAD price difference so not a no-brainer choice but definitely tempting.
On the other hand the standard M80 low end response is very good so one could argue that unless you are playing at high SPLs with a bigger amp in your future then the standard versions will arguably be just as good.
It would be nice to see how the low end frequency response curves differ between the versions (cabinet volume is the same but woofer characteristics are different) but it might take a trip up the sub-woofer tower to do that and it's not the greatest weather for testing speakers outside right now.
Sorry, thought I would have a more useful response when I started typing
