I'd say it depends on what type of android user you are. If you just user the phone, sms, browsing and occasional app then you're fine. If you're a power user then you'll just get annoyed and frustrated at simple things that you use yo be able to do but now can't.
As I've said in the windows 1520 thread, its undoubtedly a gorgeous piece of hardware and is the prime drive for me to keep looking into windows phone. Dare I say it and definitely not trying to be a troll, but if it did run android, I'm sure myself and others would buy it in a flash.
Sticking with realities though, I don't think WP8 is quite there yet for the advanced android user. I'm still very concerned that without DPI settings/apps with phablet UI, that the 1520 is just going to be running blown up phone apps, like first gen android tablets, which is not ideal.
File browser is key and offers so much flexibility. Copying and sharing photos off your DSLR, sending whatever file you want through gmail, deleting downloaded files etc. Skydrive is not a suitable replacement, especially if you're not always on wifi/limited 4G data plans.
Apps is becoming less of an issue with most of the core apps there in some shape and using 3rd party official apps is not something I worry about. It is still an issue however for niche apps. Eg Niche medical apps, a reliable CHM file reader (reference text books), advanced pdf reader/editor with the ability to underline/comment/draw in.... I can go on. Even office 365 functionality that is supposedly a huge selling point is largely replaceable with Kingsoft office which is superb sans the synching (you just need the extra step of google drive).
Then there are the core google services which have really exploded in functionality to become more than just gimmicks in the past 12 months. – Chrome browser with its desktop session synching, google now with its local contextual searches, automatic G+ photo uploader (full size backups with auto enhancement unlike dropbox).
Lets not mention 3rd party accessory compatibility with Windows Phone...ie. there APIs are so closed that no BT keyboards work with it for example.
There's a lot which is being fixed and is "promised" to be fixed in upcoming updates from MS – unfortunately thats always been the story with WP as they play catchup, which I understand being a new OS. However, 12 months on, even basic things like notification centre, screen rotation lock, separate notification ringtones, separate notification/system volumes are still yet to be fixed/only being patched now.
In terms of positives of the windows phone os, to be honest there isn't anything that appeals to me that I'm not already experiencing in android. Metro UI I don't mind but can be hit and miss with no notification centre and when you're relying on 3rd party live tiles which don't always update frequently enough for your liking (and wit no option to change). Simplicity is always touted as a windows phone advantage, but to be honest I find android simple enough if you know what you're doing and the appeal is more for perhaps people new to smartphones. As an android user, the simplicity actually feels limiting as I can't get things to work exactly how I want it to. In short it's a matter of how much I can compromise when coming from Android to wp on the software side unfortunately.
Having said all this I'd still keep looking at WP due to Nokia's hardware and their general nailing of the camera (which android hasn't accomplished fully yet), but there needs to be a lot of improvement on the software side from MS and 3rd party developers before I can fully see myself changing platforms. As good as the hardware and camera may be, my smartphone is my mobile computer replacement and the OS needs to be able to function like that.
Perhaps when RT merges with 8.1 and a few more MS and Nokia updates roll out it'll get more capable and phablet friendly. But until that time I'm keep jealously watching and admiring in awe at the camera and hardware but deep down knowing I just can't do what I want to do on it right now.
Something like Tasker or automatic volume adjustment will require homebrew, or at least an OEM app; third-party apps aren't allowed to run continuously in the background (it's bad for performance and battery life) on WP.
Here Drive will run fully in the background (battery warning: don't forget to stop it if you take a break somewhere short of your destination!) and will override other audio playback to give directions. Start Here Drive, enter directions and start navigation, then hit Start (or press-and-hold Back) and go to your media player app. You should continue getting turn-by-turn prompts. It doesn't actually pause the audio, which is annoying - you'll miss bits of songs or audiobooks, for example - but it works.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?