I think you should stay with what you know the most unless you really, really hate it.
(Which is precisely what I did with my old phone - Android 2.3.x with all that Samsung cruft won't cut it on that old phone. And even with hacking to 4.0.4, it is barely usable.
I keep the other phone because I have three phone numbers. The one in my Lumia is the contracted one - microSIM. The prepaid one is because I can't make international calls with a postpaid under a student's pass. The third number is Malaysian - I have weekly trips there.
Yeah, it's sounding more and more like an OS that's worth checking out. Not that I intend to move away from iOS; I just want to sate my curiosity.
The naming scheme all depends on the circle of company you're in. With customers, I might say Intel Core i5 (slipping in the Intel name always makes them feel better), whereas around other enthusiasts (especially on tech forums), I would say a 3570K, omitting the i5 or similar nomenclature in its entirety.
Quick question: how and why do you still have/use two phones?
I like how without doing anything special to the phone I can gain direct filesystem access to my Windows Phone in Windows, to the user-writeable space. I can't execute from there, but I can use it as a makeshift drive on anything with Zune installed.