Agreed, AC Delco filters have become absolute crap since their manufacturing has moved to china. Yes, K&N (STP is the same filter) are very high quality, but as Bison said, not a good value because of the premium pricing policy.
I personally prefer and use Baldwin, one of the highest quality on the market, but you have to find a good value to make them worthwile. I get mine from an ACE Hardware store on my occasional trips to WI. The Baldwins carry one of if not the highest "burst strength" and strongest internals on the market.
Baldwin B35S to replace PF 52. And for the biggie users, Baldwin B9