Not so much proof as one man's opinion in that post. Mind you that I actually had both units A/B'ed in my car -not some showroom- and tweaked for SQ. Take my opinion's for what's it worth but I have owned the following units in the last 15 years:
Alpine 7802
Two other 1990's Alpine models (forgot their #'s)
Sony CDX-C90
Alpine 9815
Eclipse 8443
Clarion DRZ9255
Eclipse 8455
Given that I A/B compared the two units and owned some pretty high end units, I think my opinion should count for something. That said, I still stand by my conclusion that the new Eclipse 8455 is still the superior unit for SQ. A plus to the new Eclipse models is that their crossover points and other electronic adjustments is MUCH more flexible vs. previous models -- very much catching up the Alpine! And of course, the 8455 has GPS and auto EQ via microphone is cherry on top.
Certainly the Alpine 9855 has the gorgeous display and variable LED color match is a plus. Also notable is the dead silent sound (or lack there of) when one powers up or down the amps - no pops whatsoever. The GlideTouch, IMO, is a novelty at best, sh*t at wost. Memo to Alpine's marketing team: It's a head unit, not a laptop; stop driving your engineers to design such nonsense. Alpine's SQ, while very much improved vs. their two year old 9815 model, is still not a contender to Eclipse's top deck. Mated to JL Audio 300/2 and 300/4 amps, the Alpine still exhibited harshness and graininess in the upper end; it got worst as the volume was cranked up. The Eclipse on the other hand just handled it beautifully and effortlessly as volume increased. Really top notch.
I really wanted Alpine to win based on the gorgeous display. That and because I have been an Alpine fan since they were the boutique brand of the early 90's. They certainly have not been that in a while nor will they ever return. Eclipse became the boutique brand just a little time after Alpine and have taken it's place since Alpine went way mainstream. However, the sound from the Eclipse just just so effortless and detailed. My vote is of course, spend the extra $100+ for the 8455.
Good luck. Let us know your personal findings?