Social Justice Commoner
I'm fairly sure Competitive currently matches you against people based on your team's highest MMR. So if you queue with three friends, you'll want to be sure you're all broadly on thy same level.I'll warn you then that even while Competitive may be skill based, you have very high chances of running into full fireteams who will nearly always destroy you because teamwork and cooperation are the kings in Destiny pvp.
It might be confirmation bias, but I felt like I saw this a lot when I got Recluse. At low levels, if my team was four randoms, and the enemy a 4 stack, we would outgun them fairly easily. Again, they're revamping matchmaking anyway, so who knows what the future brings.
They're (re)launching the freelancer queue, where everyone matches solo.