I'd say the FWB. Its famous in targetshooting, thats for a reason. Aeron is tsjech, that means they can and wíll have issues. More or less, easy or more complex. But thats why they're cheaper.
Drulov is a bit similar. I've heard several people having to size some pellets cause it would jam otherwise..
Why not look at sech Steyr as well if yr looking at FWB?
If yr looking at budget and singleshot, dont forget the Tau 7. YES they áre tsjech as well, but súch awesome shooters that I forgive them..