A G3 is a great gun, no need to avoid stamped receivers, just make sure it functions. The stamped receivers (which are the intended design) sometimes have issues - and that's one of the best things about these guns - it is almost always the trigger ledge that causes issues like jams - and it's extremely easy to fix. The original design is flawless, the removal of the swing down pin is what causes their problems (and thank goodness, since you can find $100 guns sometimes). I've purchased many problematic G3's that only needed 15 minutes of work to get them perfect. There are two different types of stamped receivers - HK spec and non-HK spec, most cetmes are not HK spec. You can tell because the STANAG claw mount will have sharp edges - that is an HK spec and a STANAG claw will grasp that tight and firm, the CETME with it's rounded mounts will cause you some issues. Bolt gap is easy as hell to fix - it isn't a problem, it just means the weapon has been shot quite a bit. They are great reliable and unique guns. I'll give you some posts to look over on them. And lastly, a CETME is not a clone - the G3 is the clone of the CETME.
And I already answered most of your questions already in a thread that is practically the same as this one:
The PSL seems fine and dandy until you realize all of that cheap 7.62x54R surplus ammo is highly corrosive... and that's a semi auto AK receiver. If you don't clean it meticulously every time you fire it, the gun will eat itself. I think they are really cool on the surface, but once you actually put your head into them, they don't make sense. Non-corrosive 7.62x54R is usually Prvi Partizan (PPU) and it's about $12.00 a box - more expensive than cheap .308 . If you look at brown bear cheap non-corrosive 54R it's 7.95 a box if you buy 25 boxes at aimsurplus, but that's $200 for 500 rounds - not the 79.99 you were talking about and it's entirely pointless, now you're using terribly inaccurate ammo in a sniper rifle. The 440 round cans you're quoting is corrosive ammo, 440, 880, all those bulk numbers are surplus corrosive ammo. You can reload .308. Reloading 54R is expensive as hell for the proper cases, then you have dies, and it will never be as cheap as .308. And the nail in the coffin for the PSL? The Mosin Nagant - it's more accurate than a PSL, exact same caliber, and costs $100 bucks.
Overall, they are both good guns, the PSL will be more accurate out of the box, but it will cost you more to shoot it with the proper ammo. It comes with optics, it's an accurate high powered rifle right out of the box but that's were it begins and where it ends. A G3 is a much more versatile platform, many aftermarket parts... the sky is the limit. You can do SBR side folders all the way to 1/2 MOA accuracy with a PSG1 barrel - it will just cost you a fortune - HK parts are not cheap.
Go new HK retail (and pay a fortune)
Go old HK surplus (and save a fortune)
You can put together your own G3 with proper HK parts for around $400 if you know what you're doing. They are not as easy to build as AR-15's, but I think they are a hell of a lot more entertaining.