What is your Priority Club status?
Diamond

Were you (or for multi-stayers are you generally) happy with the hotel/stay?
Indigo Melbourne on Flinders (formerly Holiday Inn)

Which room did you book and which upgrade did you receive?
Booked a standard room. Upgraded to a premium room city view before arrival, which is a bit bigger and doesn't face the back. .

How are the rooms?
Obviously, new, since this re-opened last year. They made some effort with the style, but nothing memorable. Spacious enough with a small sofa + a small table for two. No desk like in most (all?) Indigo, but the round table was decent enough for a bit of work on a laptop. No HDMI easily accessible for the TV and no AirPlay (it had Chromecast), so can't really be used as an external screen. Australian plugs only but they had USB A and C outlets so I could use that.
The bathroom had 2 sinks which was a nice surprise
The view was still of the building in front on the other side of flinders lane, I think you really need the corner room (or close to it) if you want a nice view, or top floor (I was on 7th floor). When this was a Holiday Inn they had very nice corner suites with the living room at the corner of spencer and flinder.

How is the exec. lounge?
N/A

What was good and what was bad?
Good:
- They at least follow the Melbourne theme by including good Barista-made coffee at breakfast, unlike the Crowne Plaza where I usually stay which charges extra
- Functional, decent size room. I think it had a Nespresso machine too.

Bad:
- Small menu at the only restaurant (which is also the room service menu), and on top of that some nights have a "reduced" menu so there's barely anything to eat. The food was good though, the restaurant is definitely better than when it was a holiday inn.
- Location: anyone who knows Melbourne knows this is very far from the interesting end of Flinders lane so I think they're pushing the marketing a bit too far. The Hoddle grid is not big so it's not a terrible location, but it's not a fancy area.

Value for $ or Priority Club Points? Would you return?
For work I usually stay at the Crowne Plaza which is a bit more suitable to business (bigger hotel, a bit more F&B options) and where the outside rooms have a much better view. So, unless the Indigo is cheaper (which it was in that case), I'm not sold on it. There's nothing wrong with it, but don't expect a unique experience in a hotel with character.