I have a Three homesignal (the black NEC variety)
Although it is better than the 0-1 bars of unreliable 2100 signal from the nearest 3 mast, it does have its own issues, in my experience.
There is a slight, but noticeable delay on voice calls and I often find I end up talking over the other person and vice versa. I suspect this is because of it using consumer grade ADSL as backhaul to Three's core network as opposed to low latency fibre links / leased lines.
The other thing is that data through the homesignal box is very ropey. Often it doesn't work and when it does you get timeouts. Only when I leave the homesignal coverage and onto real coverage I start to get e-mail push notifications from Outlook and so on.
Before someone asks why would I want to use data through it, well the answer is ... believe it or not, not everyone has wi-fi. My network and router is wired.