I've just switched to this
I know the MVNO companies can be a nightmare at times with customer service, but this one has been bought by its own network (EE) and is now run by them and I've been very pleased. I called to port in my number, and waited 3 minutes to reach a real person, and 48 hours for the port to take effect.
During my research, I saw a few great deals on U-Switch for LIFE, but this one beats the lot if you're a high user. From my own experience, the coverage is exactly as EE 3G network so no 'restricted access'.
I hope it helps a few of you (probably ideal for the kids!!)
You know what - thats a shed-load cheaper than the basic charge for a landline into your house!