Yeah, I had an Xperia Z some years ago and got along just fine with it. The thing is, Sony phones are so expensive these days that I can just get an iPhone for the same price. If I have the choice, I will prefer an iPhone, but that's just a personal thing. This windows phone however was truly horrible in every way imaginable. I guess the hardware would be better with a more expensive device such as the Lumia 950. But the faults in the software won't go away.

So you switched from a premium end of the spectrum to one of the cheap bargain basement models and are shocked it doesn't perform like your model that costs more than four times the price. the 640 is actually a great phone for the price. Windows Phone OS for many is far better than IOS, for others it is worse, personally I rate Windows Phone first then Android and way way down the list the slow cumbersome iOS, but it is all personal preference.

Android all the way for me ...

There's some quality models to be had with the extra loaded benefits of being an Android owner ... (I've stuck with mine for almost 3 years already.)

No, the performance wasn't any problem to me. It's not as fluid as iOS, sure, but good enough especially considering the price. The real problem is the OS with problems and missing features like there's no tomorrow. A data connection that loses its connection every few minutes is absolutely inexcusable, no matter how cheap a phone is. Constant reboots for no apparent reason are not what users should expect, even on a cheap phone. Basic features like a flashlight are to be expected, especially when the hardware itself is already there. I should also be able to connect the phone to my computer, no matter if it's a Mac or a PC. If you get a dirt cheap Android phone, you can connect it just fine with your computer or Mac. There is simply no reason why I shouldn't be able to access my phone from a Mac, there should be a option for Mass Storage at the very least.

Those are just a few examples for why the software is really really bad. And as those are purely software issues, they are also present on high-end Windows devices like the Lumia 950, which is even more ridiculous. I never once complained about the speed or the performance, those were absolutely great considering the price of the device. But the OS is just broken, plain and simple. 

i never had a problem with WP but after some years i just bought a High end Android from HTC wich is amazing and i will never go back to WP again, the lack of Google and other app kills it for me.

Still a fast and organized SW, shame about the app ecosystem.

You shouldn't have invested in a windows phone. If you want a good budget phone, get the third gen Moto G, or Apple's pseudo budget iPhone, the SE.

Even MS isn't wasting more time on Windows mobile, it was completely missing from their 2016 build keynotes.

Not trying to dis the platform, but you can get MS best apps on either Android or iOS. For now, avoid WMP. In the future, the situation may change, and I personally think it will change for the better.

For good budget android phones, check the following smartphones:

Nexus 5x

Moto G third generation, Moto X pure edition.

Never had a problem with my data connection, I use it as my access point for work almost everyday. It has a flashlight I assume you just didn't know where to look. Macs are notoriously bad with any non apple hardware, unlike iphones a windows phone can just be easily opened as a storage device assuming the OS doesn't suck arse.

I switched from iOS to Android (iPhone 5 to Moto X Gen 2). I'm very happy with my decision.

I had a Lumia 920 for 3-4 years now.
Never had a single problem that you describe... Except for tethering, but I tether over Bluetooth anyway.
I can even plug it into any PC/Mac and browse it like a USB flash drive.
It's been less problematic than my iOS and Android tablets and I use it more.

And it's been a durable phone, not a single crack in it... I have dropped it, sat on it, slept with it, even left it in the rain... Everything. Still works as fast and fluidly as the day I got it.

I also have wireless charging. Hate cables.

Ordered a Lumia 640 for a friend, so let's see if the same things replicate themselves that the Op describes.

and xboxxxx but yeah I agree, their phones aren't that great. Android all the way (even though I have an iphone..)