I've stayed at 3 Sydney airport hotels: 1) Airport Sydney International Inn, 2) Novotel, 3) Rydges.
I will never stay at 1) ever again. Was a terrible experience. Room was falling to bits. Corridors were in a disgusting state, and I couldn't tell if my meal was fish or chicken or something else. I complained to the Manager about my experience. What a waste of time, I'll never get those 10mins of my life back again.
2) The hotel was nice and would stay there again, but the shuttle was a disgrace. Waited at the curb for an hour with about 5 phone calls asking where it was. Almost took a taxi instead. Pathetic.
3) This place was great, a walk directly across the road from the international terminal, meal was excellent and service was great. If I need an airport hotel for international flight, this will be it.
Never stayed at the Stamford but looks closer to domestic terminal. Might try there next time I need an airport hotel for domestic purposes.