Tack, the claim of VHOs lasting longer may have to do with IceCap ballasts. They drive VHO lamps a bit differently than other ballasts and make them last longer. Actually, when PCs first started to get popular in the hobby years ago, one of the selling points was that they supposedly had much better lamp life than VHOs. IME however, if anything, the opposite is true (when they're running on comparable ballasts).
As for power consumption - watts are watts, so whatever your lighting system draws is what you pay for. If your system draws 400 watts it doesn't matter if it's PC, VHO, T-5 or MH. It's important to remember, however, that your system may draw more or less actual wattage than the lamps are rated for depending on the specific ballasts/lamps in question. You really have to measure the actual draw to know for sure.