Absolutely love the Saiga in 7.62x39mm
I have fired a few cheap AKs (Maadi, Norinco, Mak-90) and a Saiga. The Saiga is the only high end AK I have fired so I can't speak for Vector, Vepr, Asenal or any others.
I was never too impressed with the cheap AKs, beyond the fun factor.
The Saiga I have fired, (my father's) is like magic. One of my absolute favorite rifles to fire, despite the lack of a pistol grip, (I hate rifle stocks.) It might not be as finitely accurate as an M16A2, but I can't rapid fire with any other weapon as good as I can rapid fire with the Saiga. The site picture comes back quickly, and the rounds stay in the black. Shooting in the offhand is a breeze, and the rifle shoots well with a sling or without, (Obviously shoots better with one, though.)
After my dad installed a recoil pad on his Saiga, it removed my main complaint about the AK family, which is the short LOP. Despite having easily 6-7 times as many rounds fired with the M16A2, and a lot more handling time, the Saiga AK is the one I am more confident with. I am extremely sorry I didn't buy one when they were still legal here in Cali.
If the other high end AKs are as good as the Saiga, (And some will say they are better,) then you won't be sorry getting a good one.