I've been in Canada for a year using my UK phone, so I only get Edge due to the different bands. Surprisingly, I have survived and I didn't think I would. Sure things take longer to load and I can't really stream YouTube but you learn to live with it and you can always pick up wifi in a lot of cafes and restaurants to send images and files. But, I can send/receive my emails, use Tango/WhatsUp/Skype to instant message, Facebook, browse the web etc. It's more than adequate, you can work around the limitations fairly easily. I'm also on a limited data plan (500MB month) so at faster speeds I would hit that limit very quickly!

I will be buying a Nexus 5 when it comes out though :)