schmookeeg
En-Route
Penn Yan is expensive and my opinion over priced. While quoting shops for my O-470R overhaul, they among the most expensive and also the least amount of machining work. Their warranty was sub-par for the cost as well.
Corona Engines out of Corona Ca has good average pricing and a good benchmark for reference. Airmark out of Florida overhauls to new tolerances and frequently a lower price - just see the spectrum.
Pricing page: https://www.coronaengines.com/Engine-Overhaul
Just to add anecdata, I've had Ben at Corona Engines build several motors for me. Best one was an O-300 that went 4400 hours (1800 TBO), as well as several Skyhawk O-320s that went past 2500. He'll be doing one of my current IO-550Cs when it finally sends up the money sign. He did an IO-550B for my Vtail and an IO-520E for my last Baron. Both were humming along (~900 on the 550, ~500 on the 520) with their new owners, last I knew.
There is a sweet spot between "brand name recognition" and "non-exorbitant price" to be found with Western Skyways. They're about 15% more than a typical field OH but bring enough name recognition to add value at resale.