Rent prices are high, but I would disagree about the Pringles comment. Food, while expensive, is not outrageously so. Said can of Pringles is probably more like EUR 3.50. Besides, Pringles are bad for you, Mzungu. Shopping at Nakumatt or the German Butcher will set you back some Euros, shopping at a local grocer will not be nearly as costly.
Kigali is clean, safe and has a nice climate. No, it's not a metropolis and things can and do move very,slowly there. Having been to every nook and cranny on the African continent, I can say with certainty that Kigali is delightful and Africa "light."
Rwandair isn't a career destination but, if it gets you where you want to be, a worthy excursion.