which HU is worth buying for the price and really whats is the difference between the Pioneer DEH-P8600MP and DEH-P860MP besides one being "Top of the line"?
Ah, the difference between the P8600MP and the P860MP is that the P860MP has the Premier label(2-year warranty and supposedly it's built better) and steps up to 6.5v preouts whereas the P8600MP has 4v preouts.
I think Panasonic is somewhat underrated, and would be worth checking out at least, but throw in the fact that both of the Pioneer headunits have 24 bit Burr-Brown D/A converters, obviously the Pioneers are the better unit, though not necessarily the better deal.