Would you find WM a viable option if you didn't have the 2nd line/iPhone? I don't imagine many having two lines unless one is work issued.
Tough to say, for me... Ever since I discovered Waze, I can't imagine being on the road without it. So I'd think that if I had to choose, I'd probably choose iphone with Waze over winphone without it... Now i'm paying $20 extra per month just to be able to use Waze - the iphone stays in the car pretty much like a GPS

And the bad part is, that it's not only Waze, there are several other apps that are pretty important to me but I can somehow manage without them. And I would imagine that the chances are, that everybody has some essential apps like that, that are not available to Win10M. Moreover, just got the MS Band, MS Health hardly works with anything, there are no normal health apps for Win10M, I actually started taking the iphone out of the car to use it for some health things; then, just decided to check this MS Wallet thing, good thing that I happen to have a BOA credit card, otherwise useless (still pretty useless, cause I have better credit cards that I have to use). I was pretty optimistic when I started to write this post, but actually writing it, I started wondering why am I really doing this to myself?

A friend of mine is correct when he calls me a martyr for using the Winphone

)) But to your question, is it viable, yes it is

)) I am running a business and using the phone a lot... I was in Europe, used the two SIMs feature... I mean, it's fine. But then again, I'm very good at this martyrdom stuff

))