Currently using an old Lumia model but I'm honestly not bothered as I just use it for texts and calls only like any other mobile phone.

I bought a budget Lumia 520 two years ago. Nowadays it works mostly as an offline music player, but after two years with it... I rarely came across that much issues.

I paid a budget price for it, and got a phone that works almost as good as an iPhone. While the Music UI is slow, I got an alternative music playing app that looks and works better, PLUS; asking Cortana to play something is much quicker as well.

Everything is easy to find when looking on settings, the camera actually takes good quality pictures, and me not being an app guy I don't mind the lack of/abundance of outdated apps.

My only major grip though: No YouTube app. You have to use the browser, and after the mandatory updated to 8.1, it just gives "cannot decode video" errors pretty frequently. Seriously, you can't pause, skip, or sometimes even change the volume because the video completely stops. Videos also have a tendency to freeze video and play only audio, and zoom themselves for no reason. You can fix those by just tapping the screen, and everything else by rebooting the phone. Annoying nonetheless.

I like all 3 popular OS, but they shine on different form factors.

I'm happy with Android for my phone, iOS for my tablet and Windows for my PC.

Windows Phones are terrible! I had three in a row. I swear they kept getting worse each time I upgraded. I don't know how anyone deals with them. I switched to Android, back in October, and I've never been happier with a smart phone.

I downloaded the Upgrade Advisor, but Windows 10 wasn't available.

The 640/640XL are on the supported devices list, that's weird O_o

I dont feel like reading the OP... but the answer is get an Android.

I have a Windows phone that isnt activated and its fine. It has all the apps I care about and I can easily put media in it. So I prefer Windows Phone over iPhone for me personal needs.

I have a Lumia 950XL and I just love it.
I'm not a big app user and the phone does everything I need +a very smooth integration with all my Microsoft services including Xbox Video, Groove, Office, OneDrive etc... Windows Phone 10 is also fixing everything you are talking about from the flashlight, settings etc... Windows 8 was really they first new gen mobile OS; they fixed all of the major issues in the new OS.

I have the docking station too and use Continuum which is really neat and works like a charm.

I really never experienced such problems with any of my Lumia (before my 950XL, I had a 1020).

Ex-Lumia 1020 owner, Also own a cheap budget 640. My only gripe with WP is the app store, for that reason alone I wouldn't recommend them to anyone. Might give Android another go, or even upgrade my iphone in the future.

Download and install the Windows Insider App then; then sign with your Microsoft account.
This will unlock the update to Windows 10 preview (the 640 is still in preview); you can then just use the update feature to install Windows 10.