I've been having a play on the sim tonight and I am impressed so far. Some key differences I found:
1. The 3 App is better than the Vodafone app, it allows full control of my account and provides useful info on what to do when I want to 'do stuff', it also just works, no need to log in etc.
2. Data speed seems excellent at home where Voda gives me 2-3Mb down:
3. The automated voices on 3 are faster paced than Vodafone's, I dislike having to wait and listen to options, 3's system is slick, I set my Voicemail up within seconds, for example.
4. I actually have 1.17GB of data allowance a month according to the account area and 3500 texts instead of 1GB and 3000 that I've signed up to!
I look forward to having 12 months of good service to be honest!
I might just pay the early termination charge with Voda and get my PAC early