Polaris Lance is probably the 2nd best exotic scout rifle on m&k next to dmt, but is personally my preferred (I play on console). It's similar to the no time to explain in that they both return ammo on a crit. Good in both pve and pvp, especially gambit. May not be the meta in pvp but can hold its own. Works well with barrier and overload scout artifact mods. Thorn is a great weapon in pvp. Being able to delay health regeneration and the potential 2 tap is good. The recoil can be funky at first but you'll get used to it. Is not bad in pve as the things you pick up on kills refills some of your ammo. Is good when overload handcannon is a artifact mod. Bastion isn't what it used to be in pvp but is still decent. You might have trouble facing a chaperone or a main ingredient but can still shread things up close. It's fine in pve but plenty of other better fusion rifles exist. Note this is the only fusion rifle that can go into your kinetic slot. So I'd go Polaris Lance (just all around good weapon, anti barrier scout is the upcoming artifact mod) Thorn (ace of spades and Eyasluna will satisfy your pvp handcannon needs until you get this). Bastion (good but plenty of options can satisfy you until you buy this gun)