I had both the valhalla and the az absolutes at the same time. I preferred the az to the valhalla. To me, they were more natural sounding and are much fuller. Resolution wise, I'd go with the Valhalla's. If you have to live with them day to day then I'd go with the absolutes which are still very very detailed just not as harsh. I also compared them both to the pranawire nataraja and neither is in the same league.
In my system, the Absolutes created an almost "acid" type sound which I enjoyed but i'm not sure it was altogether real. There is possibly some overemphasis (slightly boomy but still very fast) on the lower notes. They do not sound digital, the valhallas on the other hand did make my system sound compressed, too focused, analytical and ultimately, not engaging.
I have a cable cooker and while I think it is an amazing product and has worked as marketed on everything I have owned, I could not make the valhalla sound good. But, to each his own.....
I cannot comment on the stealth although I just picked up the DREAM PC's for my integrated and CD and they are quite nice.