IMO, find a 640 on sale for new for $40.
Take it home, slap a memory card in it, sign up for the insider preview install 10 and see what you like.
The last time I had it on the phone about 2 months ago, I liked it, but it wasn't daily driver ready yet.
Not sure any phone has ever been as much bang for your buck.
$40 is like throw away pricing.
I've used a lot of different phones and OS's over the years.
And while many complain about the "app gap" on windows, most of those complaints can really be squashed just by adding a tile for a favorite web page.
I personally find nothing really missing that I absolutely need.
It's like a new pair of sneakers, after a few days of breaking them in, they start to feel like the most comfortable pair you ever had.
What I will urge you not to do, is go t the store, play with it for 2 minutes, then go online and tell everyone how bad it sucks.
An acceptable opinion should only come from people that have used it for a fair period of time.
Edit: Guess i'm late to this party and I should have read all three pages.
Looks like you have a 640 coming, great plan, lol.