Camera? Everything I've read suggests the N9's still better in most respects, including the UI.
Anywho, I'll be able to compare it all for myself soon, 900 will be in Australia soon apparently.
Don't really care about Linked-In personally...
I thought the L900 had tethering out-of-the-box or does it have to wait for Tango too? Guess it also depends on the carrier you're with, esp. in the US...
There's at least one voice-to-text app for the N9 now that integrates into the system. Name escapes me OTTOMH, been meaning to try it, haven't done so yet.
It's not a full-blown voice command system though, not sure if there is one.
Yeah notifications on WP7x doesn't even come close by all accounts.