have you decided on what type of reef you ultimately want to keep? I'm guessing since you are considering MH that you are wanting to keep stoney corals,, if your wanting a canopy and are not concerned with heat, and/or can place fans in the canopy, then you cant beat retro setups for bang for buck. the least expensive i can think of and still get good growth/color is doing a 250 PFO ballast with coralvue 14k bulb and a couple of Sunlight Supply Reef Optix 2 Retrofit Reflectors

just my opinion