I wouldn't recommend mars. Poor spread, but watt for watt(actual) they're pretty comparable to HPS. If you read thier site they actually recommend the 1600w(810w) as a replacement for 800w of HPS.
COB LED is the latest and greatest technology. Where mars leds are probably touching the 100lm/watt Mark, Cree Cobs are 150-200lm/w typ.
Grownorthern uses lumiled rebel chips. Their best chip is getting ~180lm/w best case scenerio, their issue is price. For their price you can get something with Cree or Veros with twice the light output.
Budmaster is using citiled COBs, the 130-150lm/w area, problem again is the light you get for the price.
PLC and Tasty LED are both good lights, optic lighting also. Good bang for your buck with these companies.
DIY is still cheapest, and if you own a drill and a soldering iron you're halfway there. Check growmau5 on YouTube for DIY LED info.
And HPS isn't bad efficiency wise. 150lm/w. The issue is that's light measured in 360°, suffer reflection loss trying to direct that light toward the canopy. Growing Vertical with HPS is the solution to that issue. But comes at the cost of added space(4x4 tent, 600w HPS centered, and you're only able to utilize ~12 sq ft of space(rim))