I'm considering ordering one of these sights from Tantal, the PKASV which is the over the bore model and I'd like to get some feedback from somebody who has one. Is it better than the Cobra? I'm also worried about the 1MOA dot size, that seems pretty small and I'm afraid it would be hard to see and slow to pick up.

The size of the dot is 1 to 1.5 Mil, not MOA, which translates roughly to 4-7 MOA, depending on the brightness of the red dot.

BTW, those are my favorite sights, period.

Got the over the bore model last week from Tantal and I just put it on my VEPR K 5.45. I'm impressed with the site.........well built and nice optics, prolly better than my Kobra. I really like the black dot in circle when the power is off. It mounts nearly over bore, about .25" to the left. It's raining in the Great White Nort today (surprise, surprise!) but I'll try to give you a range report tomorrow. Hozer out.  

I bought a PK-AV from Freedom Optics about 3 weeks ago for my SAR-2.  Great scope for the money.  It is nice to have the adjustable red dot but I don't recommend sighting it in on a target that has an orange background. The dot doesn't wash out but it is difficult to see sometimes.
I am very pleased with the scope.  Well worth what I paid & it should last a long time.