If you want to debate DEN vs. BOS, it is clear that BOS had a better regular season overall, more wins, better points differential. But that does not mean that BOS is necessarily the better team. I would say that in general, BOS is getting a little overhyped by the casual fan and DEN a little underhyped. In the 2 head to head regular season games, BOS had no answer for Jokic. Porzingis couldn't do anything to stop him. And Murray went off big time in the game in BOS.
As to the Brown vs. Murray debate. I see Murray as having the better top end. When he is healthy and at his best, he is a little better than Brown. But he has not been at that level very much. Brown has been more durable, leading to being more consistent. When Murray is good, DEN is good. When he isn't, DEN is much more beatable.
It would be getting WAAAYYY ahead of ourselves to start a debate about which team will do better in the playoffs this season if they were to meet in the finals. I will just say that this is the finals I expect and most likely per betting odds.