Finally got to experience one of these on the outer this evening.
First impressions are very good - much more comfortable ride quality than the old stock and they feel far less cramped due to the walk-through carriages. The fourth carriage does make a difference, even if the actual length of the train is similar. There’s definitely a noticeable reduction in noise level which is really positive.
One thing I did notice is that it doesn’t seem quite as smooth or fast pulling off from stations. It felt quite “start/stop” (as in, the train started accelerating quite quickly, then coasted, then accelerated, then coasted, all within the space of a few seconds). Unsure why this would be but I definitely noticed it. May just be the driver I had, but interested to hear if anyone else has picked up on this.
The new screens are a nice addition, but feel like a missed opportunity to include more robust PIS (or, at the very least, a “next station” display). It also felt like it took a significantly longer amount of time to open the doors when arriving at each station (in some cases, in excess of 5 seconds). On the old stock, the doors would sometimes be half-open before the train had even stopped!