The one complaint I've heard coffee experts have with percolators is the way the design cycles coffee through the heating/brewing process again and again--particularly towards the end. The heating will supposedly drive off the flavor that should be in one's cup. This problem will obviously be a problem, regardless of elevation and boiling point of water.
I've had coffee snob periods in the past. But more recently, I've used percolators sometimes--and went through a phase when a percolator was my primary coffee maker. I would not have considered it the "best" coffee ever, but I found it more than acceptable. It certainly is better than bad drip coffee. And, to some extent, I think even good drip is a compromise--it's convenient, but I've never felt it was the best possible coffee. (My vote here goes for French press.) A little off topic, but I've long had this sort of division between "good but not best daily" and "special occasion best" with coffee. My mother started this back in the 80s--she used drip coffee maker day to day, but had a French press pot for company/special occasion use.
Back to percolators, and my perception of them: there may be factors that colored my view of percolators--possibly I wasn't as sensitive to quality at that time. Water or coffee quality might have been compromised so much that better systems couldn't do much better. Or the vintage fun factor made me overlook problems.
Another factor worth pointing out: percolators do seem to vary. I have used both a small Electromatic and a small Farberware, and the coffee definitely tastes different. I think the Farberware was faster, but the Electromatic was better.
