Utah is probably better than us right now, but their path towards getting better is unclear. They have no cap space forever, and nobody on their roster looks set for rapid improvement unless somebody like Exum unexpectedly breaks out.
More than Utah and more than any other team that will be courting Hayward, the Celtics are the only option in the entire league that gives him a legit shot at championship contention. That's exactly how the organization will be pitching to him.
Gobert has gotten significantly better each of his 4 seasons, I don't know if he was one more season of that sort of improvement, but if he does, he could develop into a legit 2nd/3rd option offensively (and couple that with his defense and he is a modern Dwight Howard type player). Then you have Hood, who was banged up a bit this year, but if he bounces back healthy, I could see him scoring 20 a game with relative ease making him a very strong 2nd option offensively. Hill is a solid 4th option type player but is getting older and more and more injured. Then that brings you to Favors, is he washed up or can he get healthy and recover his form? He is only 25 right now, which is theoretically just the start of his prime. Similarly, Burks has been so injured you can't rely on him, but if he could ever get healthy, he would be a great 6th man type player. Exum and Lyles both have done some nice things, but I don't think you could rely on them.
If Hayward leaves, I would expect the Jazz to start selling off assets, which would create cap space, of course I'm not sure who they could get there to pair with Gobert and Hood.