I didn't use POR15 products before, but see many guys swear by them. Figured it has to be better than the VHT did. If nothing else just the thickness of the coating as a brush on vs spray should help. And as you said the graphite requires regular touch ups so I guess there ain't much getting around it...
Mine require an occasional touch up. I brush it on and run the engine up to 300-350 degrees and then let it cool off a few minutes. I do it three or four times and then let it sit for a day. Works for me.