It's good, but it's not perfect. Are the ABB folks still checking in?
Who said the ABB breakers are perfect?? I never saw one. 
Every company has good and bad products. ABB's are mostly good, and I'm not saying that 'cause I used to work there. So too are all the other major suppliers: the industry demands pretty much perfection and they usually get somethjing close to it.
Then and now, I'm always particularly leery of 63kA breakers (breakers rated to interrupt 63,000 amps as opposed to the standard models at, say only 50,000 or 55,000). The 63kA stuff isn't necessarily bad, but among equipment I saw from several suppliers, particularly among GIS (gas insulated switchgear - breakers) stuff, 63 kVA equipment had less margin built into it than other equipment. Most 63 kA units were upgraded versions of 55 kV designs, and in a few cases the way that extra capacity was engineered was to start out with a 55 kA unit that had been originally engineering with a lot of margin (say 15% so it was already really capable of nearly 63 kVA) , and add a bit of metal, etc, until you had it sufficiently over the 63kA threshold, to say to 66. My concern then, and even more now, is that the utilities were used to the 55 kA equipment (15%) margin), yet the 63 kA equipment had only a 5% margin. The higher rated equipment met the technical specifications but it wasn't quite apples to apples: operating and maintenance practices based on successful experience with 55 kV stuff might bump into problems with the 63 kA - you never quite know where and why that 'engineering margin" is needed or what it will get you.
I knew of one supplier (not ABB and not usually bought in the US) who did nothing to their "higher capacity" breakers but de-rate the operate temperature (compared to the lower rated breakers) in order to push it up to 63 kA. They cast an extra rib in the casing so the higher versus lower rated unit could be distinguished from one another in the field, and let it go at that: the 63 kV unit was really no different than the 55 kVA one except the paperwork called for operation at cooler temperatures. We discovered this when a customer utility's workers in a utility in central America rebuild a "63 kA" breaker with parts listed for the lower rated unit, and we noticed they all fit and looked identical. If fact they were, just given different part numbers in their catalog. Near as I can tell, this was not illegal, although it left a bad taste in my mouth.
