Just contemplating changing my Sony Z1 for a Note 4. Has anyone out there got 1 and if so, what are your initial thoughts etc? I'm going to swap from Vodafone to 3 as I find the coverage and mobile data really poor in the city. Unfortunately where I work has metal lined walls and there is zero coverage for 3 however they tell me there is an app called "Three In Touch" which allows SMS and calls through standard Wi-Fi. Does anyone have any comments on this also?

Sorry it's 2 questions in one post but any info would be great.

Thanks
Jon