Praedyth's ; it's ready to fire as soon as you pull the trigger. I use it in trials and it is a one shot headshot (obviously), and a two- three body shot kill depending on where you hit.

PVE or PVP? For pvp, it depends on the game mode. Any game mode that allows opponents to revive there teammate, the spear would be the better chose. For the other game modes, praedyth's is probably better. With that, a ram user can survive 2 body shots from praedyth's, so I would use a weapon like low grade humility over it if you are facing someone using that exotic. For PVE impact is typically favored over fire rate, but it depends on the weapon.

Spear is to slow in my opinion, i prefer benevolence or shadow of veil. Shoots faster than spear, but can still ress snipe. But between the two, i would say spear for trials and skirmish, and pradyths for regular crucible.

I have both weapons ascended. I used Praydeths Revenge for PvP and Effrideets Spear for PvE.

If you're low on etheric light and want to get one good all around sniper, I'd go for Her Benevolence with shortgaze, clown cartridge, casket mag, and if you get those 3 just let the final perk be whatever. You will have decent but not super high aim assist (better than either efrideets or praedyths with that roll), very good impact, and the combo of cc + casket mag gives you the highest ammo setup you can get, and more shots = more chances at damage. For casual PvP you don't need an ascended praedyths for a OHK head shot or two body shot kill on anything but a Goat Hat Warlock w max armor or anyone w a shield or in their super. The new efrideets really has zero to offer over a her benevolence. HB is all around more versatile, and the slight impact reduction is nearly meaningless.

can't get field scout anymore. go with revenge. #inb4nerfpocalypse

Efricheaps Spear all the way. Final round nerf will make it useless in PvP though so enjoy it while it lasts