I was in T1 yesterday (Jan 10 morning) and the F lounge and MB spa were closed. Apparently the hours are much more limited than at T4. I didn't see the lounges but the Terraces agent described them as not as nice as T4 and suggested that T4 would be a better choice on future trips. I don't think we've had any first-hand reports from someone who has actually used the new T1 lounges rather than just seen them. Given the limited hours of operation that isn't too surprising. I'd advise trying to go to T4 and only use T1 if security prevents you from getting to T4 departures (technically you can only go airside in the terminal from which you are departing, arrivals do not count). Of course you can also access the T4 arrivals lounge but that requires clearing customs at T4 (and using HEX to get to T1).