I really love Stokke chairs as well!
A friend generously gave us a pair for our twin daughters for Christmas! We have the dark cherry ones. Beautiful & our recently turned 2-year old girls love them. We weren't really considering a change from highchairs yet--the girls were fine in them--but now, we wouldn't go back. The girls absolutely love these chairs. They were just beaming when they first used them and enjoy being "big girls" and eating at the kitchen table with their parents. We have even seated them at the dinner table at Christmas.
These chairs are easy to clean, have seatbelts (and/or shoulder/seat belts, but we just fasten at the waist). They adjust as your child grows and can be used all the way until the kids are adults (supports 220 lbs. or more, as I recall). I've used them in the kitchen when using our laptop at the kitchen counter. Very comfortable and I understand very good for posture, etc. The key difference vs. the highchair is that the kids can place their feet comfortably on a flat surface so they are more comfortable than the highchair. I imagine you can also ajust to varying table heights as well.
We really love these chairs. Good luck with your decision!
G.