I managed to have a ride in 9080 today, I was pleasantly surprised.
To give them credit, it rattles a heck of a lot less than a regular e200. The ride for the most part is smooth, but it does struggle over small imperfections. At higher speeds, the motor is just as loud as a well defined diesel engine, but at low speeds it's remarkably quiet. It also doesn't seem to sway as much as the Yutong going round corners, that thing felt as though the roof was going to fall off.

The seats are also very comfortable, but we know GNE would never spec them. I also really liked the lighting effect on the ceiling.

I never thought I'd say this about an ADL product, but it actually felt high quality, whether or not it stays rattle free is another question!