I like drilling the back. I don't like the large overflow box running all the way to the bottom of the tank design. It takes up way too much space. You have to have this, because you need a barrier between the display and the bulkhead, so in the event of a leak, you can fix it without having to empty the entire tank. I've read that most bottoms are tempered anyway.
You will have to accommodate for the pvc
90 coming off of the back of the tank though....this may bring it away from the wall a few inches more than if the bottom was drilled.