[Windows Phone 8 Q&A, Help & Troubleshooting] DoogieDC:
Here is some more detail from my perspective:

Is the call quality on WP generally very good, or does it depend upon the handset?

The phone OS doesn’t have much affect on call quality – that depends mainly on your network, the handset, and your location. That being said, Nokia has a reputation for excellent phone radios and that is carried out in their top Lumias. The budget Lumias (520, 620) don’t come up to that standard, but after all, they are low-cost alternatives. HTC’s main entry, the 8X also has a reputation for excellent call quality.

If I were to adopt WP, is Lumia the way to go?

Nokia is the dominant player, almost by default. HTC has one good Windows Phone (8X) that came out a year ago. There is a Samsung phone as well.

What is the difference between a Lumia 920, 925 and 1020? (They seem very similar!)

They are all very similar with usually one differentiator that sets each apart.

920 – Last year’s top-of-the-line; it’s a great phone with a terrific camera – optical image stabilization is built in for better low-light shooting. However it is quite thick and heavy. On the other hand, since it is a year old it can be found at half its original price which makes it a good value.

925 – This year’s update to the 920. It’s the same phone for all practical purposes BUT it’s much thinner and lighter (which was the biggest complaint against the 920).

1020 – This is like taking the 925 and adding in the most awesome camera ever put into a phone (41 megapixels). It adds a little bulk, (but it’s still much less mass than the 920). If the camera component is important to you, then this should be on your list. If not, the camera on the 920 or 925 is already many times better than what you are already using, so save some money or weight and forgo the 1020.

Apps

Maps - Nokia’s HERE maps and HERE Drive (navigation) are terrific and free.

Search – Bing, of course. Also Google Search is available in the Windows Phone Store.

Browser – Internet Explorer works very well. Up until recently it was also your only choice. Now there are others like UC Browser and Nokia’s Express (server cached) browser.

LinkedIn – LinkedIn (That was easy.)

How is the WP OS on maximizing battery life?

As a whole, WP does well on battery life because it keeps the hardware down to a minimum. So you aren’t running a Ferrari when all you need is a Mini, so to speak. However it also comes down to the specific handset and apps.

Business Software

Excellent implementations of Office Web Applications, Lync 2013, Yammer, Skydrive Pro, OneNote, and Skype.

Can WP handle zips and PDFs too?

I don’t know about archives, but Adobe Reader is usually the first app I install on a phone.

Most important of all, how is the keyboard?

You realize that this will be a big jump from a BB 9320 – there hasn’t been a Windows Phone with a physical keyboard since the Dell Venue Pro in 2011. As for the virtual keyboard – there are no choices other than the built in keyboard. Most find it very responsive and easy to type on. However, it does have its faults. There is no way to type numbers or symbols from the main keyboard; you must toggle to the secondary numeric keyboard.

Are there any recommended high quality slim black leather cases for the Lumia range to protect the screen? I like book flip cases mainly.

There are many for the upper-range Nokia phones – at all price ranges. There is less selection in nice leather cases for the budget phones.

Which UK newspapers/business magazines (Economist? Telegraph?) have official WP apps?

You can go to the Windows Phone store on the web and look around:

http://www.windowsphone.com/en-gb/store