While ok for a mid-haul (3-5 hours) daytime flight, the seats are hideous for sleeping on for 3 reasons:

1. In the fully flat position, the seats drop to almost floor level
2. Your feet are rammed into a small narrow gap, making it feel like you are in a coffin
3. Many of the seats inflate and deflate for no reason, so you can be woken to the sound of gushing air and the seat getting harder then softer, then all goes quiet for 10 minutes, and then it starts all over again.

Hideous for overnighters to DME or TLV.

Not great for daytime flights either, as they can't fit all the galley items in, so its an abbreviated version of the CW service you would have on a 767 or 747.