My 9500 has 8.6 and my 8600 has 8.5. I haven't used 8.0/8.1 yet but I do have some machines running 7.5-7.6.1 that can handle them without choking like they would with 8.5 or higher and I'd like to see just what I'm missing out on with them. 8.0/8.1 are only a tad heavier than 7.6.1 and introduce a lot of new technologies and more PPC native code so I think the tradeoff is worth it.