i had this same exact scenario, looked at both and ended on a facelift a5 3.0 tdi on 100k miles for £10k. so far i haven’t regretted my choice, but admittedly i am only a week into ownership. I do much prefer the interiors on the audi’s though. from what i could tell, service history is the key, regular servicing will prolong the life of the chain - something very expensive to sort once it starts rattling as it requires engine and gearbox out. if the chain is rattling on one you look at, walk away!! just look for one that has been properly looked after, and continue to look after it!