As an iPhone user, I can chime in with my opinion.

It looks like the iPhone and 920 battery life are both pretty abysmal http://blogs.which.co.uk/technology/phones-3/best-phone-batt...

CPU and GPU for the end user isn't important. What is important is the perf of the UI, which WP7/8 have always been buttery smooth when compared to iOS and Android devices with better hardware.

I'd also say Nokia is very closely behind Apple in build quality if not on par. And their form factors have been great as well.

iPhone/iOS definitely has a better ecosystem, but the apps on WP8 are getting better.

Apple better than Nokia in build quality? Oh my... Do I need to bring out the drop-tests various blogs have done?

Sure bring whatever you want. The build quality of iphones is attested to in scores of independent reviews and it's not the same thing as drop test resistance.

For me: When a phone 'requires' a case to protect it from gentle use, even of putting it on the table so it will not get scratches is absurd. My iPhone 5 got scratched up before my case arrived, and I was so careful with it. I attribute this to 'build quality' also, it's not just how it feels.

I think Nokia phones are more "sturdy", exemplified by its cheap phones that just won't break. Apple is more meticulous I'd say. I have a Lumia 920. There are just tiny little seams and creaks that one wouldn't find on an iPhone.

Here's battery life from a well known blog:

http://www.anandtech.com/show/6914/samsung-galaxy-s-4-review...

No Lumia on there but I think that matches up with the general btty life rating for iphones. Some nokias in this listing:

http://www.anandtech.com/bench/Smartphone11/349

"CPU and GPU for the end user isn't important."

It certainly can be for certain apps.

"WP7/8 have always been buttery smooth when compared to iOS and Android devices with better hardware."

I'm not sure why you've lumped iOS with famously jittery Android (at least historically, 4.2 seems to have solved lag) since iOS is usually cited as the standard for smooth interface as in this initial WP 7 review from Josh Topolsky: "probably the most accurate and nuanced touch response this side of iOS4."

http://www.engadget.com/2010/10/20/windows-phone-7-review/

The battery life metric I care about is: how long will the battery last after I've been using all kinds of weird apps for a year.

That's where iPhone seems to excel. On a fresh install of Android, using just one built in app, it seems fine. But eventually the phone fills up with stuff that seems to drain it. Not sure how Windows Phone fares on that front.

Absolutely that's a problem with Android. It's a natural consequence of having a platform where apps are free to access pretty much any hardware in the background with no review (that's a good thing if you're a developer though).

However, Android gives you tools to see which apps are using the most battery, and you can uninstall them if they're a problem.

Recently I noticed much worse battery life on my nexus 4, opened up the battery stats, and saw 30% of my battery usage was the consequence of a messaging app I don't use, deleted it, and got back to normal.

In this regard WP8 is very much like iOS and not even close to Android. Apps are 'tombstoned' when they are not the visible app. So no matter how many apps you install, when they're not open, they won't use battery.

Battery, build quality and form factor are not better for the iPhone. Battery's about the same, build quality is similar, but iPhone loses points for being either easy to scratch (black 5) or easy to crack (4, 4S). Apple in general makes stylish but not robust phones. iPhone loses on the form factor because it really has only one that is acceptable - the 5. I am typing this on a 4s and the screen is too small and the shape does not feel as good in the hand as the round polycarbonate Lumias.

CPU and GPU don't seem to be so different subjectively. Both are smooth.

The apps are vastly better on iOS, even the ones that are on both platforms e.g. one cannot insert rows in Excel for WP 7 or add annotations in Kindle. Support seems better for Apple, as Lumia 800 and 900 customers did not get WP8, while the older iPhone 4 will get iOS 7!