The sole problem was that the air-con was rubbish - simply did not cool the room and turned itself off if one touched the room control panel (forcing a trip to reception to ask for it to be restarted). Opening the window helped, but the M9 dual carriageway outside is very, very noisy.
Everything else was great, notably the terrace bar and restaurant on the 8th floor.
If the air-con in your room works, the Sirius Hotel will be just fine.