We also did the Test Sleep this past week, and it was entirely legit. And honestly its a wonderful option for CDG transit. Its extremely close walking from CDG T3 RER terminal. The beds are HUGE (takes up about 1/3 of the room). They did an excellent job insulating the rooms from sound. Wifi is free, and check-in/out can be pretty quick since its all done through a kiosk. And if you select a "runway" view you might just be overlooking the Concorde...
Downside is service was pretty bad (granted it was a test sleep), no one knew much of how anything worked (the couldn't fine luggage tags to hold bags, they "ran out" of the free cocktails, only some breakfast items were included others were 50% off but it wasn't clear what was what).
Its also a bit on the trendy side (if you've stayed at Cosmopolitan Las Vegas or SLS in LA that'll be a fair comparison).
They're opening rate is now 79euro (or 67.15euro if prepaid) which is a steal compared to the Hilton right next door for 189euro. They're supposedly opening the next location in la defense so look for another sleep test offer there if you're interested...