Ultimak's gas tube scope mount is pretty popular among the AK connoisseurs, particularly when used with a Micro red dot scope. I ordered mine from Primary Arms, along with their Gen.3 Micro Red Dot sight (which is discontinued, I think, replaced by Gen.7 model) at a reduced price. The Gen.3 sight doesn't really co-witness, unless I set the rear sight to 800 meters; good enough to get the windage ball-parked. The Gen.6 and Gen.7 sights are supposed to co-witness properly on the Ultimak mount, but I can't personally confirm this.
The Ultimak mount gives a nice low mount, just be aware that after a few magazines, it will get hot enough to burn your fingertips if you're not careful, and not wearing gloves. I wonder if cheaper optics will be able to take that kind of heat for long. The Primary Arms sight is holding up so far, but I noticed that the heat was transferring to the Picatinny mount screwed to the bottom of the sight after a few magazines. By all accounts, the Aimpoint H-1 and T-1 sights take the heat just fine, but then the Aimpoints cost more than a lot of AK rifles.
The Ultimak gas tube mount clamps onto the barrel, which means it's not easily removable for cleaning, which may be a problem if you shoot corrosive ammo, and a lot of the surplus ammo is at least mildly corrosive. The mount/tube is aluminum, but when it's clamped onto the barrel, you really can't get at the gas block. I didn't have any trouble installing the mount on the WASR-10 with the K-Var plastic handguard with heat-shield, but the wood handguard that came with the rifle would have to be chiseled out to clear the straps.
The Ultimak mount is way better than most of the dust cover scope mounts, most of which don't hold a zero (stay tuned over the next few months, I want to get the new TWS mount for a 5.45x39mm AK). It's not as tall as many of the AK side-rail mounts, and it won't interfere with side-folding stocks. It's a good, solid, low mount for AK type rifles, just be aware that there are some trade-offs.
Ultimak Home Page
The mount reviewed here is the M1-B model, Scout Mount without side ports. Ultimak makes mounts to fit many of the AK variants. Check the Ultimak site for more information.