The lumia is actually to be as blunt as possible, fucking marvellous.
I doubt you've used one.
I hate the fact that apps are not retained in memory long enough. They always start over. Also, launching an app from the home screen launches a new instance instead of resuming the current instance.
Notifications are even more terrible. There's no way to access previous notifications. There's no central place where all notifications live. You can't access them from the lock screen.
Yes, all these are quirks I've found as a tech savvy user. Because of these reasons, I cant see myself ever using WP.
Besides, just the fact that you cant run unsigned applications (and there's no viable "jailbreak") is an instant turn-off for power users. So, to suggest that these people will leave Android is hilarious at best.
Regarding notifications; you know about tiles right? They have status on them i.e. unread count etc. A notification is pretty just a poke in the ribs to check the tiles rather than a queue of things to do.
Jail-break and run unsigned apps? Yes there is for nearly all devices - see xda-developers.com. I really don't care about this myself though. Mobile telephones have never been open platforms. Even Android is a fragmented minefield in this respect.
It's just different.
I spent 2 days with a loaned galaxy s2 first and it had none of the above. It was slow, clunky and inconsistent and pretty damn hard to get it to sync with my pc. It also lost outgoing emails when plugged into exchange.
The three other people I've shown it to (android users) remarked at how it is quite better than the diatribe against it and they found it intuitive.
My wife got a lumia 710, and in many ways it's a better phone than my s2, the quality of the software is noticeably better (even of the 3rd party apps). My next phone is probably going to be a lumia.