UK, Three vs. Vodafone vs. O2

Hi everyone,

I'm moving to England and planning to get a phone. After looking few everything that I could find I more or less settled on Three, due to them having unlimited data and calling home 3G/4G is cheaper then an actual call, but I'm looking for some hands-on advice.

I'm going to be in London and I know that all three providers are starting their 4G service soon.

My top 2:

1. Three - Due the unlimited data

2. Vodafone - their 4G plans seem to be okay and it comes with Spotify Premium which is nice, but it's only 2gb/month.

I'm planning to get the new iPhone or a Moto X (if they make one available by the end of september) or maybe the Nexus.

So does anyone have any advice on which provider is best and why in London?