I think personally I probably give it an 8? Good chapter and interesting with a nice surprise at the end, but perhaps slightly long winded in Aizens dialogue. Not that I'd really complain about it, dialogue tends to equate to plot xD
what do you expect everyone to do, for the last however many chapters we've sat through grimmjaw, szayel and noitora.
Finally we get to see a real villain and he looks like he's being villainous! The entire HM arc would have kicked ass if we'd got some real Aizen moments, as it was we effectively saw fights against fodder :/