So is someone rated 2000 with the average player he plays being rated 1500

better than someone rated 1700, with the average player he plays being rated 1800?

That can depend on other factors. Such as there last 10 or so game results give u a clue and the percentage of wins/loss/draws ratio overall.

But 2000+ should indicate that they are indeed better players overall then the 1700+ player, even if not by a whole lot.