So far the glass is fine. We’ve had a couple of sunny days here and I didn’t notice any particular heat on my head. The top glass is actually quite dark and has some IR-reflective coating. It’s probably a comparable amount of light compared to a normal sunroof (more area, but less light per unit area).
I won’t say the panel gaps are perfect, or even as good as my BMW. But they’re totally fine–nothing ridiculous like touching or misaligned seams. The worst I’ve found is the chrome on the driver door where it meets the jamb; if you laid a ruler flat on it, it would tip a bit. I suspect it could be fixed if I complained, but really it’s not a big deal. I’ll go through with a finer-toothed comb this weekend.
I sat in the back and it was totally comfortable, but I’ll grant there is the issue of a low seat–or, put another way, the footwell is not so deep. I’m pretty short so I could stretch my legs out and be fine. A taller person would have to live with the lack of underleg support. Probably not great for long distance trips. I had a 6’ friend in it yesterday; I forgot to ask if it was comfortable but he didn’t complain about anything. Front seat was fine for a 6’5" guy.
For noise, it’s basically silent at lower speeds (say, <50 mph). I don’t yet have much time at higher speeds and was listening to music, so I can’t really evaluate it, but there was nothing untoward there. I’ll try it without music at highway speeds next chance I get.
The ride is great. I may have different standards coming from an older 3-series with some sporty non-stock bushings on it, but it’s downright cushy in comparison (but without any sense of bounce or floatiness). Handling is fantastic; easily on par with the BMW. The steering could use more feedback, but only this morning did I realize I had it in “normal” mode, not “sport”. It’s not bad at any rate; pretty typical for a modern car, but I’m used to more feedback. Will update later on that front once I try it in sport mode. Hopefully I can make it up to Skyline drive (local curvy road) this weekend to test the handling a bit more.
Rear visibility is certainly worse than my BMW, though I didn’t have a backup camera and that makes up for a lot. It doesn’t seem to be a problem yet. It seems a lot of modern cars have a high waist (safety reasons?) and so probably this is a common thing.
Biggest annoyance so far is that I can’t shift directly from reverse to drive. I have to come to a stop, keep my foot on the brake, then shift to drive. I miss the ability to realign myself in a parking space by giving a little pulse of reverse to back out, and then in one operation accelerate forward again. Probably more of a manual transmission thing. Wouldn’t surprise me if modern automatics had an interlock here (old ones didn’t).