Hi
Personally I wouldn't touch an android phone, because I find android is too full of bugs, although regrettably I have a Google Nexux 7 (2013).
I currently have a Lumia 520 which is amazing for a cheap piece of junk! It doesn't do 4g and it has a rubbish 5mega pixel camera. And the sound is rubbish during phone calls (you have to make sure you have handset on loudspeaker and not put it to your ear or risk getting deaf). However, having said all that, the WP8.1 is nice and smooth.
Ive just bought a Lumia 930. Unfortunately, this expensive piece of rubbish is boxed up and waiting to be returned to Amazon, as its got known faults, ie phone overheats, qi charger frazzles phone, double tap to wake doesn't function properly. Apart from that the camera was pretty good.
Even with the above comments, I still wouldn't use android phone because of too many bugs.
As far as Apple are concerned, I wouldn't use any of their products as they took freeware software, put their own proprietary wrapper around it, and sell it in hardware for mega inflated prices. Also, as far as im concerned ITunes has killed off the music business so that the only people getting rich out of it were whatshisname of Apple and the record labels.
WP8.1 is worth persevering with in my opinion, as I think that when the die hard Apples and Android get over themselves and realise that the manufacturers are profiting out of what was originally freeware, and try out wp8.1 they will all swallow their words.