Nothing magic here. Would you buy a car with 280k on it?
If you're asking, I presume you're not into fixing.
Rule of thumb is there's no free lunch. You could get lucky or you could spend most or all of the difference between a low mile and high mile purchase in short order.
I love how everyone talks about the engine. There's about 1000 other parts that see wear n tear as well.
In general, high mileage is for DIY people and low mileage is for those who need a mechanic for repairs.
And just like everything else mechanical, it's situational. High miles AND a stack of records for the upkeep and maint of the rig is less risky than high miles and "never had a problem." The propensity for a bunch of things to fail or need work at those miles is much greater if all the work has been "deferred" or the previous owner has used up all the "luck."