I stayed at Karim's place while visiting Geneva with 4 friends for a weekend, and it was a perfect home-base. It has everything you want to have in an Airbnb, and is clean and well situated. Self-check-in is smooth with photos of the steps to get in, and it's in a neat part of Geneva, right by a bus station for getting around to places a bit further away.
The one problem we had is that early Sunday morning an upstairs neighbor started construction around 5-6am. This isn't something Karim has control over so I didn't downgrade my rating, and it was only that day.
Nonetheless, a great Airbnb that I'd stay at again!