There is almost no difference between the efficiency or the damage. Here’s some numbers: Let’s assume you land six shots on someone in a row and you’re doing 100 damage per shot, here’s how the damgage numbers would go for each:
Efficiency: 100-225-325-450-550-675
Damage: 100-200-350-450-550-700
So it’s more dependent on how many shots you land on one target. At one; no difference. Two; Efficiency wins. Three; Damage. Four and Five no difference. Six; Damage. At that point someone most likely backed up or is dead though. Six shots from Marquis is a lot of damage.
I guess if you are really on point with your crits you could use the first two shots to break a shield and combine the 50% amp with a crit for massive damage. But overall I think Efficiency is better simpley because it’s easier to use and yields roughly the same results.
I think the gear you are using is good. Attack damage, health regen, max health balances marquis to stay in battle and do damage. I basically focus on the same stats. If possible try to get gear which boosts attack damage as secondary effect. You can switch the attack damage with attack speed if you like to shoot fast.
some tips to keep in mind would be…
-Get used to the recoil and aim for crits against any character when you have the chance.
-Destroy turrets and shepards on site. After you get rid of those, try to focus on healers and tanks.
-Always be aware of the enemy when sniping at a risky spot, check the distance you have against them. Especially melee characters that can jump on you.
-Don’t stay too far away from your team.
-In a competitive match you wouldn’t/shouldn’t be receiving any heals. The less healing you receive is better for the healer so he/she can focus on healing tanks and attackers, reason why I think the regen gear is especially important.
-Place reveal Houdini behind or aside you and your team when fighting against stealth characters. I’ve caught a lot of pendles by just throwing it behind.
-Ping the character who you are going to snipe to let your team know. It helps those assasins to secure the kill.
-Use bindle blast wisely.