I don't do 'domestic' as I am not from the US... I only do WorldWide...
My prediction range is 850M-1.2B, so basically picking a round number 1B.. yes, I know it's not professional, but I am not pretending to be one... like i said, none of us have the metrics to be so sure of ourselves and I have always respected everyone's predictions... it's just a prediction...
And what I base mine on is:
1. Hype / Marketing (the marketing in some countries have been stellar, though lacking in a lot of international markets)
2. Brand Recognition (you can't get bigger than Superman)
3. Great fun, action packed movie for the GA...
4. Consensus that it's a very good movie (if not the best) - which we already have...
5. Pre-Sales of tickets... Fandango already said it's the fastest selling movie of all time... and I checked at my local cinemas, most seats are already sold for the popular time slots... (even though marketing is almost non-existent in my country)