I'll chime in. I see NOTHING changed other than the chip, chasis, footswitches, and LCD screen, maybe RAM. This seems aimed at the touring pro (at risk of scorning Pod HD Pro owners) who have shelled out for what seems like a now inferior product.
It's definitely about computing power. More RAM only improves performance when you need to cache data to a disk or flash memory. Maybe the chip itself has more cache, which is faster than off-chip memory, but I think it's clear we're looking at more raw processing power. I doubt that the HD's algorithms are so large it has to ditch the ones that aren't processing and keep reloading them from flash.
I can attest that the HD500 footswitches are sub-par, and the upgrade is probably good. Heard way too many stories ab footswitches not working. One of mine occasionally gives me grief and I don't even tour with it. Don't use it live, so I can't say if the LCD is an issue or not. Can't hurt to improve contrast...
The raw power is welcome but the overall architecture is still bogged down. Why not add more effects blocks? Dual output? IR loading?
WHAT THE ____ ARE THE DEVELOPERS IN THIS COMPANY DOING?!?!?!?!
And the best question. Why in the ____ do the demo pics of the unit show NINE, YES NINE, effects in the chain. It's a BS photoshop mockup, not a picture of the actual device, which supports a maximum of 8 effects. Stinks of false advertising.
The only thing I'd use this for is to use the additional power to fit reverb in patches I otherwise couldn't, or an extra effect or two. I have lots of patches like that. But unless I can hock my HD 500 and get a 500X, spending less than $100 on the turnover, it's not worth it to me. And there's a snowball shot in hell of that happening.
I'll be waiting for the next gen to come around. I'm hoping Digitech or a dark horse will put out an amazing product, and maybe a new Kemper generation isn't too far away and used gen 1's aren't much more than $1000.