Overall, I would give the Naha SmartCondo 4.5/5 stars. The location is good, close to the Yui Monorail, the rooms are top notch in terms of being modern, clean, and immaculately maintained (even by Japanese standards). The kitchenette is as usual small, but highly functional, an optimized for the space available. The communication from the manager and staff was great. I was able to stay an extra day with a minimum of fuss.
So why would I hold back 1/2 a star? The area is actually relatively loud. This is partially accounted for by the car wash next door which beeps and blares voice instructions to every customer. The geometry of surrounding buildings seems to amplify the normal street traffic noise. For light sleepers it may be a bit of an issue - or with the window closed, the AC on, and both blinds drawn tight, maybe not.