I have been using One Stop for our overhauls since 2008. We've done over 20 engines with them in that time and I only had 1 with a problem which they took care of immediately. They are a small mom-and-pop operation with a half dozen or so great people. They try to keep their prices reasonable which is very difficult to do in aviation.
Yes, they had a fire last summer and lost almost everything but as of the first of the year, they had their repair station certificate back and are in full operation in a new building right next to the Oceanside Airport.
Yep, have had several cylinders done there, and had my Citabria's O-320 Majored there as well. The fire was a setback, but they are full up again. Great prices, no nonsense business.
They overhauled a cylinder for me a few weeks ago. It took them 4 working days. Price seemed reasonable and it looked nice with everything freshly painted. 25 hrs on it so far.