So, I signed up a plan with Fido yesterday, and picked the nexus 4 to go along with the plan. So far, it's been pretty good. Battery life appears to be quite reasonable with the wifi and nfc switched off. Whilst the big screen is nice, I find it actually difficult to use it one handed - unlike my experia ray or iphone - attempting to reach the other end of the screen makes me fumble it. I think bigger screen phones are better used two handed.
I'm not a fan of the android 4 MTP connection. USB mass storage device is just much more convenient.
The camera also feels quite crappy compared to the sony. I felt the experia ray's camera has better autofocus performance, especially in low light. I also experienced the auto white balance not detecting the white balance properly under artificial light - but the experia ray handled the exact same situtation perfectly.
Also, the default resolution of the nexus 4 is 4:3.... can't figure out how to switch it to 3:2 yet. Hopefully it can be switched, as 4:3 is just not my thing. The UI of the camera application is cool when i first got it, several hours later it just gets in the way. The experia ray's is just straightforward, easy to use.
Once I've got my apartment and all settled down, will definitely have a look at getting one of those micro sim adaptors so I can use the micro sim in my experia ray. For my needs, I think I much prefer the experia ray.