I've stayed there multiple times and had a great stay every time. For the location and price they charge I think it's an awesome option in Melbourne and I enjoy it a lot more than a lot of other hotels there.
I've had a great upgrade every time after booking interior rooms and the buffet breakfast has always been great. Staff have been amazing every visit.
As for early checkin I've always had great service from them on weekend stays in Melbourne when I fly over from New Zealand which normally means arriving around 0900 or so. On a couple of occasions I've had rooms available immediately, and when I haven't the latest has been around 11am or so. Staff have sent me a SMS message to advise when the room has been ready.
Is the hotel perfect? No it's not. Room sizes are on the small side but it's not like they hide that. The hotel is a million times better than most US Doubletree's I've stayed at.