I think the feeling is almost the same for everyone: even if processor/memory on newer phones exceed our n900, there is not real replacement.

I'm one of those tempted by the Galasy S2, however, is manufactured with cheap plastic. Regarding Android: I've neved used it.

Iphone5: I've been tempted by the iPhone4, however, I'm an OpenSource/Linux lover.

At the end, I think I'm waiting for the N9.

Anyway, after OverClocking+Swappolube+SpeedPatch+CSSU my n900 is kind of a new phone, I can wait maybe until Christmas to think about changing.