Virgin Superhub (1) vs Superhub 3

My ISP is Virgin and I currently have a Superhub (1) which they supplied. Speed tests
say I'm getting 70Mb or so with a cable connection, which is fine for my purposes. My problem is that the Wifi signal is poor in some parts of the house.

I have read claims that the Superhub 3 puts out a stronger wifi signal, and I can get one from virgin for £20. Has anyone here had experience of doing this upgrade? And if so, was wifi coverage improved?