We statyed at the SLS last night and it was ok. Its a boutique hotel, so it doesnt have the big Las Vegas feel/vibe to it. I liked the decor of the lobby and rooms.
My 2 gripes were the odor - smells like air freshener was being pumped in the casino and even the hotel hallways and rooms to cover up 50+ years of cigarette smoke from the Sahara. The second thing I wasn't a fan of was there was no door on the bathroom, insufficient blackout shades. Vegas sun is bright! Especially if you're out late till 5am and want to sleep a little...
Overall was just ok. Wouldn't go back.