I have used Windows Mobile devices from the 2003/WM5 up til 6.5 (HTC HD2) then jumped ship to Android for the past 5 years and had a number of devices including the Note 1 (wifes old phone), GS3, GS4, Note 2, Note 3 and GS5 over a 15 month peroid when I worked as a Channel Rep here in Western Australia training stores on the devices, after leaving the job I had to buy a new phone and bought an unlocked Lumia 630 ($220 AU) it is a great phone and got me introduced to WP8.1 (even updated it to GDR1 - Love the folders options), and yesterday I bought the L930 had to take it back this morning as it had a dead pixel, the store swapped it on the spot and I completed a restore and I am back in business.
In my personal view the 930 blows the GS4 out of the water and even can go head to head with the GS5 (minus the IP67 rating) in fact I have found the 930 to be faster and smoother than the GS4/GS5 devices, as for apps well I can still get all the main apps I used on Android -
* Facebook
* Facebook Messanger
* Instagram (Beta)
* RSS Reader - via NextGen Reader^
* TapaTalk (paid app on Android) - Looks cleaner on WP
* Flickr - via Flickr Central
* Skype
* Weather - via Weather Flow^ now on both my 630 & 930
* Twitter - Offical App and now Tweetium^
* PayPal
* My Vodafone
* Linkedin
* File Explorer - (Used to use My Files) via Files (Microsoft)
* Battery Monitoring App - via Battery Performance^ (Great graphics, wont detect battery capacity if using GDR1)
* Adobe Reader
* OneNote - Better on WP than Android
* Word/Excel - (Used to use Polaris) via Office is cleaner and looks good.
* Social Chat - (Used to use ChatON) via BBM
^ Paid Apps
The only app I can't get so far is my banks app - Westpac, however the Mobile Website is just as good, they have stated they are working on an app. Also the GS4 is currently $599 AU and I bought the 930 on special for $534 (was $729) which is so much better than the GS4, even the GS5 is $899.
Well thats my 5 cents...