It's not, nor is it really close. This Cleveland team is incredibly flawed, their defense was still terrible tonight, Boston got a ton of open shots but just missed. This wasn't a great basketball game by any stretch. LeBron's Miami teams were much better, the first Spurs-Heat series (especially the last two games) was some insanely high level basketball. Those Miami teams were terrific defensively, this Cavs team is still a mess defensively. But grinding out a road win in a game seven with this team is just another impressive point on LeBron's resume.
I'm not saying this Cleveland team is better in the sense that they're more talented. I'd even say they got a big break by not having to play a full Celtics team.
I think they play really well as a unit though. Those Miami teams were good and all but their talent was above the team chemistry from an outside perspective.