Great product for the benefit of at least allowing many to remain connected to the internet.
However, depending on 4G congestion in your area and the package that you're on, you may find Hybrid Connect to be extremely slow as I understand that the download speed is capped at around 50Mbps.
If BT can uncap the download speed then it would be more helpful for those of us who are on Full Fibre 300, 500 and 910 connections.
Also, beware Digital Voice users, as soon as my Hybrid Connect kicked in (I was showing off to a family member), it totally screwed up my Digital Voice connection when the main broadband reconnected. Not sure if it is just my set up or a firmware issue.
I would have hoped that Digital Voice would still be activated if the Hybrid Connect took over but sadly not at this stage.