I bought my AP used as well. The only real options at the time were 5150 and Stratified. I don't doubt things have come a long way since I was on Cobb.
Eurodyne is falling behind. Logging sucks (but is much better with an SL1 and simos tools

). However, there are some damn fast cars out there on it. I was really happy with my tune from GLS Performance; however, I really wanted wanted the ability to not have to push the clutch in to start, be able to change maps on the fly, add flex fuel capabilities and RAL.
I've added a bunch of hardware since I started this journey. 2 turbos, MPI, LPFP, sensors...for someone who's constantly changing things around, OS is a great solution. I have a buddy who's running EQT hardware and tune. Went from stock block to built block, 535/PM4 to RS3 pump, XL turbo to Typhoon...everytime he made a change he was charged to retune. Some people can afford that; I can't justify it anymore.