I would say 75% of the time I have a fusion rifle equipped. After the nerfs to shotgun range and sniper ammo capacity, I started using fusions more. They seem unaffected by the special ammo nerf and deal solid damage without the need for precision hits, and do so at a range far enough from the boss to be safe (usually). Plus they look and sound cool--except for Omolon ones. Actually all Omolon weapons look bad and sound worse. This is in PvE by the way. I almost never enter the Crucible. The fusions I use are Ashraven's Flight (void, the one Lord Saladin sold a while back), Darkblade's Spite (solar), and Hitchhiker FR-4 (arc).