Interior is nice, rooms are above average, but parking is a NIGHTMARE. Their underground parking lot is a dark labyrinth that's just as unpleasant to drive in to as it is to drive out.
Pro Tip: There are two exits out of the Cosmo parking lot. Do not, I repeat, DO NOT try to exit the Cosmo parking lot to Las Vegas Blvd (this is the exit closest to the Bellagio). You will be backed up for 45 minutes trying to make a right turn because there isn't a stoplight (just a stop sign) and waiting for the endless hordes of tourists to stop crossing.
Exit the Cosmo parking lot via Harmon Ave. You'll thank me later for this.