Just a few data points from a recent stay.

Applied SNAs and cleared 4 days out to a Federation Terrace Suite. Was surprised since I got the "we're working on it" message 5 days out but did clear a day later; I don't know if I've ever successfully cleared SNAs after initially getting denied under either SPG or Bonvoy.

I was glad to get the upgrade since the standard rooms here seem quite small; the suite I got is basically a standard room with an extra bit on the end so I could easily get a sense of how small the standard room would be. My plan had been to cancel and go to the Westin if my SNA didn't clear, since the Westin seems to have more bigger rooms available. But I wanted a proper suite, and the Westin doesn't offer those on SNAs, so when the Sheraton came through I went for that. (I could have also gone for the Marriott but it seemed to be more tired in general and offered only lounge breakfast rather than full restaurant breakfast at the Sheraton or Westin.)

The suite itself at the Sheraton did the trick for a 5-night stay in terms of being big enough that my husband and I weren't tripping all over each other, but it's not an especially large suite. The living room area is small with just an armchair and a 2-person sofa; you won't be hosting any parties here. There is a tiny balcony off the living room. The living room and bedroom are separated by a door, although the bathroom does cause issues in terms of one person being able to be asleep while the other is awake (see next paragraph). The suite is also on the north end of the building which faces a bunch of low-rise buildings in the nearby blocks and thus gives you something of a view, though of nothing in particular. But it's an improvement on most of the rest of the rooms which are fairly close to other buildings and don't really have any view at all.

As in the standard rooms, the bathroom has a window looking out into the bedroom which can be covered with a shade. Which you'll want to do unless you're traveling by yourself, since even the toilet is fully exposed otherwise. (Other hotels like the Westin Sydney have a similar setup but it makes a bit more sense there as the toilet is in an enclosed WC and the shower is likewise enclosed, so conceivably you might not mind having the rest of the bathroom open to the room there, if you were staying with your SO.) Annoyingly, the shade is not light-blocking though, so if you get up to use the bathroom in the middle of the night and turn the bathroom lights on, it pretty much fully lights up the bedroom and may wake up another person who remains asleep.

The rest of the hotel was nice enough, although it is perched in a small plot of land so everything is a bit more compact and vertical than you might expect. The gym is decently well-equipped for a hotel of this size. The indoor pool is fairly nice though long and narrow, so if you wanted to swim laps you'd probably only be able to if no one else was there.

Breakfast is in a lovely space off the lobby on the first (i.e. one floor above ground) floor, and was generally pretty good. I haven't seen a detailed review of either the Sheraton or Westin breakfast so still don't know how they compare, but would suspect the Westin might be a bit better -- there was no smoked salmon out on the buffet at the Sheraton for example, although you could order a smoked salmon (or various other types of) omelette included with the Platinum breakfast. But overall it's a solid breakfast offering. The croissants and other pastries, in particular, were a lot better than I would expect at a Sheraton.

This was my second time in Melbourne, and I stayed at the Park Hyatt previously -- between the two I'd more likely return to the Sheraton just because the PH is badly in need of an overhaul, but that's also not really a fair comparison. Really, I still don't think there's a perfect Bonvoy option (or even any major hotel chain option) in Melbourne. The location of the Sheraton was okay; it's close to the PH but handily a few blocks closer than the PH is to Parliament station and several tram stations, which was useful. I think the Westin may still be a better location, but I'm less sure of that after this trip -- being right by Flinders St station at the Westin would be nice and a lot of trams run up Swanston St., but we also found the Bourke St trams very handy and the Sheraton is better positioned for those, plus it's an annoying walk up a steep hill heading east from the Westin. We'll see what the forthcoming W will bring. (Near Southern Cross station there was also a construction site with signage saying they were building a St. Regis, but it also looked like potentially the construction was stalled or abandoned?)