Only been to Oban once and that was a few years ago. Didn't have any issues, staff were helpful and friendly. Didn't come across any "red tape" either.
From an airfield's perspective OOH permits can be a bit of a pain to deal with, lack of fire cover, insurance, security/access to/from the airfield when nobody is there, dealing with fees, parking, various other reasons.
If it's a small quiet private strip with no commercial activity then it's not usually a problem, commercial ops at any size of aerodrome however bring a number of additional complexities that your average PPL will be largely ignorant of. Security, Access Controls, Insurance, Fire Cover, ATC/FISO etc. Whether it's liked or not by PPLs these airfields do have CAT activity and the above services are mandated by the CAA/EASA and DFT.