Probably no huge surprise that I'd choose a Windows phone considering my history.
Some plusses:
Maps and GPS navigation work even when I'm out of range of a tower (which is a substantial bit of territory hereabouts)
I really, really like the wireless charging pads. Lay the phone on it any old way it is starts charging. There is a car version that just went on sale in England. Should be here in the states soon and I'll have one then. Put the phone in the cradle and it starts charging. The NFC (near field communications) built into the phone allows programming of the pad so when it is in the cradle, the GPS/navigation app starts.
NFC allows programming small patches so you can set one up for the nightstand that auto-silences the phone when it's on the tag and won't disturb when you're trying to snooze. Other tabs or patches can be setup for different locations or situations limited only by one's imagination.
Not a lot of bloatware was installed on my phone but what I didn't want was easily removed.
Flat tile interface is more to some folk's liking. Jony Ives must have sorta liked it too because the new I-phone announced yesterday sure looks a lot like it.
Built in Office seems to work on everything but files I've protected with a password.
Camera is decent and the Xenon flash + LED is better than the sole LED offered by others. Camera is certainly not up to par with my P&S Panasonic with its bright superzoom lens. Past models of the Nokia had a 43 Mpix sensor and it looks like one is on the way for the next Lumia.   Normally, a small sensor with lots of Mpix is bad news in low light or high ISO required when lights are dim. Nokia's solution with the old model was to combine output of all the pixels with software to bring back low light performance and do away with the noise associated with lots of tiny Mpix. Such technology will no doubt find its way to dedicated cameras also because its too good not to.
NFC allows sharing among phones equipped with it to transfer stuff by just tapping the backs of two phones together and holding them there until the transfer is complete.
Phone is very fast and responsive and the OS has been stable so far.
Supposedly, the Winphone platform is the least susceptible to malware. That however, remains to be seen??   

Minuses:
I-phone has a couple apps  that I'd like but have not made it to the Windows store -- yet.
I'd like something like an Otterbox but my phone is too new to have much available along those lines -- yet.