Note that to make it even more complex, BT's package pricing via cash back sites such as topcashback and quidco can be different to going via BT direct. It's not simply the standard pricing with cash back as you'd expect.
I found the G4 box to be quiet (i had the plusnet version, 95% the same box) but have now switched to BT for the UltraHD package.. Whilst this is £5 more than the standard entertainment package (£15 instead of £10) the extra £5 gets you HD for entertainment and BT Sport channels, the new UHD channel as well as a newer box with 1TB hard drive instead of 500GB. This box has a fan (the G4 doesn't) but i've not noticed the difference in the week I've had it.
I got £180 cash back whilst paying £10 for Infinity 1 and £15 for TV. Unfortunately i just missed out on additional sainsburys vouchers which seem to stop and start all the time.
Ashington (Northumberland) Exchange