Zuska, I feel like we have been over this.
MH is extremely intense lighting. It is fabulous for clams, SPS, even some LPS. Will it burn some corals? Probably. Of course, you can also try to create caves and overhangs with your aquascape to get around this. Over a 65g tank, you will probably want 2 MH bulbs at 175 or 250w. (It's 36 in tank, right?) You might be able to get away with one if you invest in a good reflector, but it will probably be darker on the edges. This is good for your corals you don't want to burn, but may not give you an aesthetically pleasing effect.
For a 36 x 18 tank, you would probably need at least 6 36" T5 bulbs. The light will be a little less intense, but your tank will stay cooler. You may have to put clams and SPS up higher. Because they are less intense, you may need more lights to cover the whole tank which could equal more electrical usage.
You keep asking which is better. The answer is .... it's whatever you prefer. Whatever is best for what you want to keep.