Okay,Dr. Foster and Smith doesn't carry the 30'' model is why.The Sundial has individual reflectors which is another reason why they are a better choice then the Aquatic Life.
I was thinking along the same lines as far as added heat issues, with the sundial having fans and a timer built in it seems like it would be a more hassle free system and since it will allow to me keep about anything im planning on having it will more than likely be the way i go.
With a MH on a tank that size you may find the addition of a chiller would be necessary. I agree T5 lighting would be the way to go and provide more than enough for your lighting needs.