I'm not terribly impressed myself. I do like that they provided this for free...it was a good move. But the rules revealed thus far aren't that impressive. A couple of interesting things are easily homebrewed into an existing 3e/PF game. That said, it doesn't mean I won't support WotC, but that decision is based more on what they do with the Realms itself more than the rules.
I have a dream that one day, all game worlds will exist as one.
I have liked what was presented in the D&D Basic Rules. I'll wait for the Core Books to see the final version.
But I'm not sure about the amount of spell slots for spellcasters above the 10th level character. I know the rules of magic have changed, but it seemed very few spell slots for high level characters.
For what it's worth, they've said that Basic is essentially copy/paste from the PHB. There will be extra stuff int he book, but the rules, spell progressions, etc are the same.