You picked 3 of my least favorite bikes.
Sunday and V10: Both of these are built to race. The Sunday has a low Bottom Bracket, long wheelbase and a super slack head angle. If you wanna rip it up and race all day and all night, get a Sunday. For other DH disciplines (AKA, just DHing for fun) then I'd like to point you to a different DH bike (Morewood Izimu, Turner DHR, Rotec R9, Giant Glory). The V10 is sort of in the same boat as the Sunday, pure bred racing rig. Nothing wrong with that, just they're built for racing. I REALLY recommend test riding them. I test rode both a Sunday and V10 and didn't like either of them, and I used to think those bikes were the bee's kneez as everyone on these boards thinks, test ride them if you can.
Stab Primo: I've never been fond of Kona to be honest, the Stab's design has been around for a really long time. If the Stab is your thing, then by all means do it. From what I get from the Stab is that its heavy and sluggish, I never see them on the trails now-a-days. Correct me if I'm wrong though, I've never ridden a Stab.
I think the Glory is right up your alley. Its a pretty beasty downhill bike, with the right geometry and price. It seems more than durable, at least compared to the Sunday (Tightening linkage anyone?) If I had to choose between the options you gave me, Glory all the way.