Since I've been at AT2010 in Saitama I can already say I like it much more than AT2009, but it's rather because I just prefer the less futuristic style.
AT2010 has some arabian style (don't look back, inspire), some kinda middle ages style (ballad, love the dress) and the cute section this time in more sexy that cute and was awesome.
It also has Alterna and Memorial Address which was too awesome to describe. the only thing I didn't like was her encore clothes and hair (bow, sorry, I really hate it, can't help it) but that's nothing comparing to the whole impression. However, I must admit AT 2009 definitely had better MC, the games were so funny
I'm just afraid the 50th single anniversary that will be at the DVD will lack some of the unique performances, I'm afraid that eg the awesome Memorial Address may be replaced with some single song, etc, that would be bad.