As a coach of a HS program (CBDS, NC) that has traveled in and out of state for 4 years now, I have had opportunities to compete against teams that were both coached and uncoached. I can't and wouldn't make any unequivocal statements about teams that are uncoached for the simple reason that most teams take on the quality of their leader(s), whether those are captains or coaches. We have competed against uncoached teams that knew and applied the rules better than many coached teams. We have seen great, spirited play from an uncoached team and turned around and played a coached, chippy game.
I would qualify the differences in two ways: accountability and direction. My players know that they have free reign to make their own decisions but that, if I deem their decisions to be bad ones - especially injurious or discourteous ones - they will be held accountable. I also know (or hope), when walking over to shake another coach's hand, that the same goes for the other coached team. It's quite difficult to hold your teammates and peers accountable on that kind of level. For the second case, the average team is bound to have more longevity and success with a coach. That doesn't absolve the players from their responsibilities in promotion, recruitment, and retention, it just adds a stable voice to the process. A coach who is older, more experienced, and mature can often provide insight into individual games that players on field level can fail to see.
I commend the teams who do it year after year with no head support. However, for those teams who have the capacity to invite someone else into your huddle - do it. For their good, as well as yours. It's a rewarding relationship.