Stayed one night while visiting family near by - be warned DO NOT FOLLOW GPS - you will wind up trying to enter a secured residential area. But you will need a car if you stay here because it is far from everything.
The hotel was expensive, $200 - but it is Miami, but it is beautiful and there are lots of little extras from almonds at the front desk to jelly beans in the room. It smelled lovely and was very clean. The pool area is really interesting with cabanas, etc. and the rooms are huge, with kitchenette etc.,
The best thing about this hotel is the staff - everyone is SUPER friendly and that doesn't happen a lot in Miami Beach. Really we can't say enough about the smiles and service we received. But hard to say the great staff is worth the fact that there is NO soundproofing in the rooms - we were woken at 5:30am by the family (we are assuming it was a family of very large people) showering, packing, rolling suitcase and arguing about how much time they had to get to the airport.... You can hear everything in this hotel.

Stayed here for a couple of nights prior to a cruise. Hard to find and looked a bit naff from outside, but inside is a very nice, clean and friendly hotel. The room was large and well kept. This is a very good place to stay, apart from there is no where to eat. The nearest is the hotel across the road. Very good food but not cheap!

The Quarzo lacks of a clear identity, after staying with them for 3 nights it is still not entirely clear to me whether it is a vacation rental or an hotel.
It is too expensive for being a vacation rental (about $380 a night), but has not enough services to be considered an hotel.
Besides this, there is a blatant lack of personnel to be considered a luxurious property. Basically any type of manual operation (ie. Housekeeping) may take ages to be completed.

PROS
- Extra big rooms, with a full size kitchen and a living room
- Modern and tasteful décor
- Nice Zen Garden

CONS
- Noisy Air Con (to the point that it is preferred to shut it down and suffer the heat).
- No view from the rooms
- No restaurant or even a place to have breakfast
- Small pool, with no heating and limited sun exposure (freezing)
- Poor TV offer (just 20 channels)

All I can say is that I teared up when I first saw the bedroom. The room was so clean that we could eat on the floor if we wanted to. Everything was meticulously organized and beautifully decorated. Wherever you go within the hotel, there is this soft and relaxing music playing and amazing scented candles/mists all around. The beach is just a few steps away and there's all the structure you may need - chairs, towels and even beach toys for the kids. This is by far the best hotel I ever stayed in the Miami area - and I've been to Miami more than 10 times already. The staff was really amazing and pampered us to the highest level. We had our one-year-old with us and there was even a teddy-bear for him when we got in the bedroom. We definitely plan to stay at Quarzo again and - as far as I'm consulted - there won't be any doubt on recommending to all our friends!