Stayed here overnight to visit Luna Park. Excellent location just across from the Milsons Point train station, harbour bridge & a short walk down to Luna Park + Sydney Harbour.
Room was very clean, spacious & comfortable. The staff were great even changing our room to allow an earlier check-in time which was greatly appreciated.
Had dinner at the Curve restaurant which was very nice & reasonably priced. Although the breakfast was ok I cannot recommend it for the price. Was $28 each for the buffet which was fairly basic. Could have gotten better value from nearby cafes etc.
Overall very nice stay & would stay again if revisiting this area.

The location in Milson's Point is awesome. It's right across from the train station (yes, you CAN hear the train in the morning.) It's nice because it's in North Sydney, away from the uber-high traffic area of the CBD. But a nice stroll across the bridge, or a quick train ride, takes you right into the main city. Also, there's some very interesting restaurants 100 meters away in Kirribilli (try Kirribilli Hotel for drinks, Garfish for great seafood or Stir Crazy for (relatively) affordable Thai Food.

Rooms are good sized w/ couch or two chairs plus very comfy bed. Clean and efficient would be a good description. Get a front-facing room or else you're staring into the apartment complex 5 meters away (and yes, they can stare right back into your room). Bar is nice, restaurant food is quite good and there's an outside terrace overlooking the harbour.

Plus: Breakfast is A$ 20.00, but you can often get it comp'd into the rate, or coffee guy right outside the front door, or small breakfast nook one door away. Fridge in room. Olympic pool and fitness center are a short walk away -- ask the front desk for comp passes (you can get one per person per day.) Oh, and it is really Olympic as in it's where they had the swimming during the Sydney Olympics!. Always cabs out front.

Negatives: Train noise might be bothersome for some.
They charge for internet service (really Vide?)
They charge 1.50% extra for paying by credit card (really, really Vibe?)
Service is... well...examples.
1) Room wasn't ready at check-in, but they offered to upgrade me to one that WAS ready -- for $75.00 per night.
2) Pipe broke in ceiling above room and flooded the bathroom at 3.30am. Had to pack up everything and move to another room. Not their fault, but didn't comp anything on the room rate at first. After arguing with manager, they finally agreed to knock $100.00 off of a $279.00 per night rate (and mind you, I was there 8 nights.) Definitely should have comp'd the flooded room.

Tips:
There's little brochures in a rack by the elevator. The one for the Vibe North Sydney contains a 2-for-1 coupon on dinner. Take it and use it!
Food is really expensive in Sydney. Sneak a sandwich out of the breakfast buffet for lunch. The staff doesn't mind (in fact one of them suggested I make a sandwich for 'take away.')

We booked 2 rooms for 5 nights 26-31/1/12 through a deal on Travel Zoo. The hotel was very handy right across the road from Milsons Point Station. That is the only good point. Now the Bad ones - Upon arrival at reception were told we needed to pay an extra $50 deposit per night per room even though our accommodation was already paid for. Then we were advised that our rooms were on different levels (11 & 7) which we were not happy about so the said they would move one of us the next day so we were both on the 7th floor. We had to carry out own bags up to our room, no such thing as a porter. The bathroom in 713 has mould in the shower, the tv remote has tape on the back the tv is so small we couldnt read the names of the tennis players they were cut off. The curtains dont close properly because of the broken tracks. The laundry was right accross the hall which made noise all day and night. The next day when our friends were moved down to the 7th floor next to us they advised reception their aircondioner was not working, then we went out for the day. When we returned at 8pm that night we found the airconditioner was still not working, so theye rang reception again and they new nothing of it so they sent up a nice repair man who said if he couldnt fix they would be moved to another room again. So at 9.30 at night they had to move rooms again back up to the 11th floor. Also they were advised they had to move their own things as there was no one to help. Overall very poor service. The breakfast was very basic but the view from the restaurant was pretty good.

Stayed one night for work.

Reception staff very pleasant and friendly, room itself was large, clean, beautiful view, comfortable bed. Room service dinner was tastier than most I've had and was delivered quickly. So far, so good.

However.

The air conditioning unit began emitting random squeals at about 2am, waking me up. The man on reception was clearly familiar with the problem (ie, it had happened before), advised me to turn the aircon to a different fan speed - and while this did immediately fix the problem, it didn't fix it permanently. Woken up again at 4am and 5:30. Result: one very grumpy YetAnotherWorkTrip.

On the positive side, when I complained about this upon checkout, the staff immediately apologised, took appropriate action, and promised they would let me know when the problem was fixed. (I'll update this review when I get their notification). I don't know if this problem is restricted to one room or is common across the whole hotel.

So I do recommend staying here, but check that the airconditioning unit has been fixed, or turn it off (which is only possible if you turn all the lights off too).