I rode on one of the new Class 379 trains on Friday. It was the standard Bombardier UK product and looks and feels just like all their other "Electrostar" type units. The seats were rather hard. I had a numb bum after 40 minutes sitting on one.
It transpires that they are having a few problems with their Auxiliary Converter Modules (ACMs). The same problems first surfaced with the same company's S Stock being delivered to the London Underground. They had an embarrassingly long "sit down" with one of them a few weeks ago. Apparently, the problems are due to the software.