I stayed last week at the Rialto while on business in Melbourne. It was great all the way around. I was a bit wary of the previous reviewers who were critical of the fact that rooms have windows into the atrium, rather than to the street ... but how else do you have windows in a city hotel sandwiched between other high buildings? If you have to be able to see outside, perhaps it will bother you, but it didn't make any difference to me, as you do get outside light from the atrium. (Just keep the curtains closed if you're less than fully dressed :)
The concierge staff is FANTASTIC. Paul, in particular, gave amazing service. I really cannot remember a better concierge staff in any hotel I've stayed in, even some true five-star joints.
The rooms were clean, and mine was plenty big (two double beds) as was the king room that some friends stayed in. Amenities were typical (shampoo, etc). It is a great business hotel and also a reasonable choice for a fun visit if you don't plan to spend all your time in your room (just b/c it isn't a "resort" type hotel). Location was fine ... I wasn't doing a lot of things in Melbourne, but it is right on the tram route and within walking distance to at least two major stations ... also within walking distance to the river, Flinders St (and Flinders Lane for good shopping) and plenty of good restaurants.
The restaurant is extremely overpriced for breakfast ... if yours isn't included in the price, I'd recommend eating elsewhere. There are a couple of good cafes across and/or down the street. (most of them were not open on holidays or on the Saturday following, although not sure if that's regular for a Saturday.) The McDonalds across the street has a McCafe coffee shop that will do if you're in a hurry.
I'd stay there again and recommend it to friends.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.