Involvement of the combustion chamber indicates that compression seal is compromised. I have heard of cases where metal erosion (on the deck of the block and/or the head where the stock gasket sealed compression around the bores) has been "repaired" by sanding the area(s) with a Dremel or similar grinder with a wheel. This process removes more metal from the places where is most desperately needed for clamp load on the gasket. Imperfect o-ringing also can compromise the compression seal.
A copper gasket is a simple device, usually soft for conformability. It may not last "forever" due to combustion heat but if it fails soon after installation in the compression seal, it is most usually a result of incorrect installation, which can also include under- or over-torquing the head bolts. Worse, some have gone to studs and then torque them well over 120 ft lb with slippery lubricant like moly on FINE threads. This increases the clamp load tremendously, to the point of sometimes warping the block or head. The cylinders can be rendered partially "hexagonal" by this procedure as well, compromising ring seal.
If a copper gasket, or a stock gasket, fails in the water jacket area only, it is sometimes caused by poor "goopum" or spray on sealer, sometimes by poor surfacing (either too rough or not flat enough), and in the case of using a 12 valve gasket on a 24 valve, by leakage from the exhaust side water passages that are not properly sealed by the gasket--a 12 valve gasket has a steel strip along the exhaust side whereas the 24 valve gasket has "roofing paper + red goopum" there to seal these passages.
I don't know how much boost you are running, but I suspect installation procedures, cleanliness, and flatness of the surfaces to be the culprits, not the various manufacturers of the gaskets. In particular, there is virtually nothing to go wrong with a copper gasket in the cylinder seal (compression) area. Similarly, if the surfaces are good and clean, it takes a lot of cylinder pressure to fail a stock gasket.
I have never failed a stock or stock + 0. 020" head gasket. I run up to 50 psi boost and have never resurfaced the engine block. I am using the factory surfacing job on the replacement head.
Hope this helps.