NBA 2k9 vs 2k10

I already have 2k10 and have played it a lot, so I was curious about how 2k9 compares to 2k10. I'm thinking about buying 2k9, even though 2k/elite 11 comes out soon . Is one of them clearly better than the other, or are the relatively even? How does the gameplay/realism differ? And are there serious or annoying bugs in 2k9?

I actually preferred 2k9 to 2k10 to tell you the truth. Either way, after playing the 2k11 demo, it seems quite a bit better than both of them