My HH3 has worked since installation in June this year. Has needed a couple of re-boots in that time when I couldn't access the Broadband connection.
My first Modem died after a day and was replaced. All been well since then.
BT / OR wall-mounted the Modem without being asked. Some posters have said it overheats, but mine is hardly warm. There may have been an issue with earlier ones.
People have said desk mounting the Modem is fine for them.
You can have up to 30 Metres of 'Data Extension Cable' installed by OR from the Master Socket to where the Modem is located.
Don't forget, Modem and Hub need a separate mains plug connection.
Allergy Advice: This post may contain traces of Meerkats.