I personally prefer the DMR because I'm more of a medium to long range sniper that likes to hide in places away from the main field of combat. I usually sit back there with my DMR and a shotgun or something for CQC in case someone sneaks up behind me.
I use burst fire weapons in about every fps I've played since the shots are much smoother, less of a kick and I'm usually able to get every bullet on point. Although the br in Halo works out differently even firing it compared to the Dmr seems the same like my trigger finger doesn't matter. So I'm really undecided but I'll say Dmr for now until I notice an actual difference when firing the weapon.