AK quality has to do with a couple of things:
A) parts quality- where did they come from
B) build quality- who built it
Pre-ban Romanian like the Romak, Ratmil, and Cugir are all examples of good romanian AKM/AK74s. Quality is still not on par with russian guns.
WASRs can range from decent to extremely bad. Most of the bad reputation that AKs have earned over the years (in America) are from poorly assembled WASRs from century arms international (CAI) which usually include poor quality parts as well. Most of these guns were built using surplus romanian parts( well used and abuse) as well as rejected parts. Common problems include, canted front sight tower, excessive mag wobble (due to poor conversion of the magwell) as well as other issues. When they used to be sub $250 they were worth it, but not they are quite a bit more and your better off avoiding them in general.
Bulgarian and russian AKs are generally considered the best in the post-ban era. Arsenal has been the primary builder for bulgarian parts kits and their quality is top notch. Russian AKs come into the country as unconverted Saiga rifles. Many companies do simple conversions, but only a few like arsenal actually return them to AK-100 spec. The difference can be a few hundred dollars, and its up to you whether you want an authentic looking AK or not.
The best AK variants to be ever be made were Valmets and Galils, but those are ridiculously expensive and parts are almost impossible to get. Chinese AKs are very good quality but you will pay a huge premium since they have not imported any of them for a long time. They are not generally worth the expense unless you want a collectors peice. So I would avoid all three of these.
Egyptian AKs were the WASRs before there were WASRs, and the quality of the fit and finish is generally poor, but they are serviceable.
There are also a number of American "made" AKs out there, but non of them are 100% american made. Generally you will pay a premium for these AKs even though they are not much better than a WASR.
Companies to stay away from at all costs
- Hesse/Vulcan/blackthorne (horrible company that changes names)
- Lancaster arms (a complete crook)
- Elite Arms ( complete tool and a crook)
All three of those have huge amounts of complaints with the better business bureau as well as other legal troubles with local municipalities due to fraud claims.
Companies to be careful of:
- Century arms international: On occasion they can make a decent weapon, but it is often a gamble and even a careful inspection may not show all the problems. You will often spend just as much fixing the problems as you would have if you had just bought a better AK in the first place. They are banking on the fact that they have the cheapest product on the market and an ignorant consumer base. This philosophy is shown with their 1 year warranty that starts as soon as their rifles leave the factory (not when you take first ownership) which means it can often be expired or nearly so when you buy it as the original owner at a gunshop. Not everything with the century label is crap because they are the largest arms importer/exporter, they do bring in alot of stuff that is simply stamped with their name. However their conversions and kit builds should be avoided, and this especially includes their Tantels which had 5.56 barrels installed instead of 5.45 and constantly keyhole. They knew about this problem, yet continued to do nothing about it. If you want a Tantel buy it from another manufacturer.
Long story short, if you want a good quality AK you can not go wrong with an Arsenal AK. Several other builders like Red Jacket and Krebs are also renowned custom builders that do excellent work.
If you want the best Accuracy you going to find it from an AK100 series bulgarian SLR-106 in 5.56 from Arsenal. 7.62x39 does not lend itself well to long range accuracy because it is ballistically similar to the .30-30. Saiga .308s are great platforms if you want to customize it into a DMR.
As far as the Stamped vs Milled debate. Milled guns simply have a heavier receiver that is more expensive to make. They are neither more accurate nor more reliable. Basically they only add excessive weight. If this does not bother you and you can get one for the same price as a stamped gun then go for it, but there really is no benefit, which is why nobody made milled guns once stamped AKs came along.
Also there are lots of AK variants.
WASR-10= AKM
Arsenal SLR= AK-100 series
Saiga= AK-100 series
You will also find numerous AK-74 kits out there.