the coated bulbs I am using are 8400lumens/per @ 4000k vs 5900k for the crappy clear mv bulbs, they made my tiny plants from the last grow flower BIG for their size, and the growth of these new plants is quite impressive vs my last grow with just floros for veg. as far as i know the mv works fine, it just isn't nearly as efficient as even floro, but these two 8400lumen lights replace quite a few cfls and floro tubes (I use the cfls in my house to offset the cost of power). Of course I still have 4 26w cfls and 2 2ft warm white sets for side and rear lighting, this area is cast with some 24,000 lumens over a 3x1.5 area, the bulbs are 10" from top of soil in reflector hoods and I now have some 5ft vertical to play in, my last grow I only had like 20" max vertical (tops were bent) so my plants were like lolipops, I learned a lot.
I certainly would like to upgrade to hps, but 150w hps setup costs $120 retail here, my mv setup cost $40 for two fixtures, and $26 for two coated bulbs, I will get an hps soon, but money is tight and I already had 1 mv in possesion, so for now, the mv works just fine.