For me, it would be similar to getting a haircut, tattoo, or dentistry from a none professional.
I would always go to a talented, competent, and able person, but not to an armchair expert down the pub.
Unfortunately main dealership staff are seldom talented, competent, or able.
So my vote is for the small independent mechanics who are more trustworthy, and will get the job done.
Any kind of service history is OK.
- Dealership while under warranty.
- Independent workshop or self employed mechanic for timing belts, wheel bearings etc.
- Owner servicing records for new filters and a basic oil change if the owner is competent.