You read a lot of complaints about the Selespeed, but I think they've improved it a lot.
It still takes some getting used to and I think you are better off shifting manually rather than relying on the "city" mode, which seems to stay in first too long for smooth starts (which must be why some report lurchiness at low speeds). More fundamentally, City mode doesn't let you fully take advantage of the performance on downshifting, engine braking etc., which would be a shame to miss out on. It's fantastic!
Once you get used to shifting, it is very smooth. Do not drive it like a full automatic, which it is not. Whether in automatic or manual shift mode you need to ease off the throttle on the upshift to get a nice smooth change, so you might as well pay attention to the revs and shift manually to time the change/throttle properly to avoid lurches and other surprises. Don't stay too long in first unless you are gunning it.
Selespeed gives you really quick automatic double-clutch on downshifts at speed, which sounds incredible and pushes you nicely back into the seat.
It's not a sports car, but it's got lots of headroom at motorway speeds.
Something I'm still sorting out is how they've programmed the selespeed to automatically downshift as you slow down, meaning that if you are coming into a fast turn and try to downshift yourself you may unexpectedly drop two gears. Not nice.
Steering is a very nice weight and although the suspension is a bit stiff I don't think it's as bad as people complain. It is a very confident car in fast corners.
I've only had it over 500 miles so far, but for what it's worth nothing's gone wrong, even with the electronics (which I assumed would have a glitch or two by now). I think they've done a lot to improve build quality.
Storage space is the only obvious problem so far (but I knew this from the test drive). The glove box can't even house the owners manual, and the various storage compartments really can't take anything more than a deck of cards. The boot is not very large either. But you know all this.
I think you get a lot of value: much cheaper than what you pay for a 3 series to get the same performance, same for Audi TT, Audi A4, Mercedes SLK etc. (assuming the reliability holds for me, of course!!)