Bought my kid a 650, bargain phone.
Loaded the backup of his previous WP8.1 1020 and was up and running in no time. Took a while to download all the apps funnily enough.
I use the RBS app because it uses a PIN to access the accounts quickly once set up. I don't do much with it but it is handy for checking the balance to see if I have been paid.
I do think it is a shame WP10 doesn't get the love, as ISPs and Mobile operators clearly show, two choices are definitely not enough.
Even if MS simply produce one or two devices, I will stick with it I think, since, like a previous poster, I don't care about apps-du-jour and being incessantly harangued by ads.
I prefer clean, downloaded maps and clean(er) search results, with noticeably less fake news.