Just to put up some photos and a mini review. I've had 2 stays at this hotel now, one a few days after it opened (never a good idea) and another about a week after. In both cases I had very early flights so I can't comment on the breakfast, but it is a reasonably good option in view of its connectivity to T4 and the other terminals. On both occasions the check-in process seemed to take a long time, I've been somewhat spoilt by Hilton's Digital Key system where there is no check-in experience at all. On the first visit there was only one person on reception, and one couple in front who seemingly had a vast list of questions to run through. The agent then walked them to their room, leaving me to look at the empty reception desk until the agent had returned!
But I guess these are minor things, the room is well equipped and very quiet. One of my stays was directly overlooking the main roundabout at the entrance to T4 and yet it was totally silent in the room. There is a goodly set of power sockets in all the right places, including UK, USA, Europe and USB chargers.
The tunnel is accessed from the Depatures level right by the El Al check-in area, which is on the far right as you enter the building. It is signposted but one sign is missing, just keep your eyes on the right side with El Al on the left side.
The best local alternative to the CP at its price point would be the next door Hilton T4.