@Pupik Review! Review! Review!
The windows tint electronically; you choose one of five levels from transparent to nearly opaque. There's a slight bluish-aquamarine tint, and it takes about 20-30 seconds to go dark to light and vice versa. The windows are taller, but the two I had seemed a tiny bit blurry, when looking at fine detail.
It's a wide-body, but there's a good bit of height, so you have to be very talk to bang your head on anything. It's laid out like a 767; United uses 3-3-3 seating; one thing I liked was that the window seat didn't have a seat support brace that restricted legroom, so my backpack and legs fit nicely.
I had standard seating, no extended legroom, and I didn't opt for the lay-flat business seating was an extra $500 on the day of the flight. Economy class isn't too bad for a four-hour flight; however, it would probably be a pinch for anything over six hours (I'm 5'10").
In-flight entertainment was top notch, although I just browsed it to check it out. I was reading a book and took a 40-minute nap (it's rare I get more than 20 minutes).
The engines (I think) made a weird howling noise during taxiing, like a wolf or dog; it might have been cargo pressurization, as other types of planes make odd noises during that time. I was sitting aft of the engines, they weren't noisy, although not quite as whisper-quiet as the 777's were on take-off.
Ailerons seem to have more movable elements, which was cool to watch for the last twenty minutes of the descent into Houston.
Large overhead bins; you can mount a carry-on piece sideways in any row. Interior lighting softly changes color, air vents were adequate (the some ones on the 737-900 seem a bit miserly with airflow). Didn't use the lav.
The crew seemed a bit friendlier and met drink needs nicely, although they charge for any snacks. I prepared in advance. They also supplied all passengers with pillows and blankets, which is the first time in years since I've seen that available.
From reviews I'd read on seatguru.com, I was expecting a cattle-class experience, but it was actually quite positive compared to my usual jaunts in mid-sized aircraft. 👍
Photos later on...although I didn't get any of the outside of the aircraft, since security and ticketing were long lines at SFO's International Terminal G.