I'll attack this one 2 weeks too late, but hunting season just ended so now I have time. I have had the attack pants for years and the prana zion convertible pants for a couple years. I have used both for hunting and scouting well into winter. I wouldn't get the zions unless they were convertibles.
IMO the vertical ventilation zipper on the attack pants is just a silly feature compared to the ventilation offered by convertibles. It's been a hot damn year in CO and even at the end of September I have gone to shorts mode during the hunt multiple times at 9-13K elevation. I take double sided Velcro and wrap it around the lower part of the pants just below my knee, so the lower part of the pants is more like a gaiter and I never remove it from my leg. Great ventilation and I still have lower leg protection. The vertical zipper on the attack pants were a cool idea to a problem that was already solved by convertible pants.
If you are bow hunting, I think the attack pants are quieter moving through the brush.
Durability, I have gotten equal service out of both for years.
DWR, don't know and don't care. I want a breathable warm weather pant and anything that hinders that is mission defeating the purpose of warm weather pants. If it isn't raining hard enough for rain pants then it is just a temporary cooler. The bigger priority is which pants dry quicker come sunset and cooler temperatures. The Prana convertibles is a lighter material that dries quicker.
Pockets, both my attack and zion covertibles have hip pockets on both legs. The zion's have two zippers per hip pocket, top and front so that's pretty convenient. The zippers on the back pockets of the attacks keep them from filling with debris if you spend some time on your butt glassing. The zion's have no closures on their back pockets. The front pockets on the attacks are at a weird angle that is kind of awkward.
Personal convenience, well I've already talked about the convenience of pants going to shorts. Now I'm going to talk about Piss. Who the hell decided to put these short fly zippers on pants obviously don't have men's plumbing. The Prana Zion fly zipper measures a mere 4 inches. My jeans are 6 inch zippers. So what this means for me is when I hang my willy out to piss, I have to lower the pants so there isn't pressure on my urethra. A PITA when you have a pack on with a hip belt and then you need to loosen your pant's belt just to piss. A common occurrence for me after some coffee. The attack pants fly is only slightly better at 5 inches. Not sure about the attack pants fly having two zipper heads. I'm sure somebody out there unzips there pants from the bottom rather than the top, but I'm just old fashion.
Sizing, me being unAmerican, I am taller than I am wide. A definite inconvenience finding clothing is you are tall and lean. So the attack pants were short in the leg for me. The zion offers 32x34 so that was an okay fit.
Camo, well it is cool and it seems to be more useful hiding from other hunters then elk. I have had very close encounters this year with elk while wearing grey solid colored zions, maybe not the 12 yard encounter I had with the attacks but still close. However, this was the first year I decided not to do any calling so it's not really a fair comparison since the elk were not seeking me out.
YMMV.