I'm going to take a different approach. I think you have lived in darkness too long. It's time you saw the light. I would highly suggest you buy a used WP phone, something in the mid range of price and capability. The exact model will be determined by your carrier supports.
It's been stated that all LUMIA phones will be able to upgrade to Win 10. Using this phone with WP 8 or whatever it has on it will allow you to get familiar with WP's and the OS. If you like WP at the level it is now, you will only like it more on WP 10. If you don't like it now, sell the phone and go about your business. You will have learned something new which is always good and the expenditure won't break the bank.
Your decision but I offer this for your consideration.
By the way, this site is the absolute best source of help and information on WP phones. We have sister sites that offer good support on Android and IOS phones as well.