Koi Kemang is a great cafe, particularly when it is quiet before the brunch/lunch rush.
We've eaten there a number of times over the last couple of years, sometimes just for a coffee or small breakfast. The food is generally good (not great) for the common fare if occasionally a little pricey but it is pitched at the expat market so that is to be expected. Their earlybird breakfast deal is decent but we usually forgo it since we're after a real treat if we make the effort to go out.
The decor is quite modern and it's worth exploring the furniture store upstairs if only for amusement. Fortunately they do separate the smoking and non-smoking parts of the restaurant so you're not subjected to smoke.