My family and I spent a week in the Viva Palmanova and had a wonderful time. The staff are excellent, from the lifeguard who kept a discreet eye on our 3 year old when he decided to change pools without telling us to the restaurant staff who were so friendly and helpful.
Overall, the good points:
Very family orientated, great facilities for children (and for adults if they have the time to use them!)
Excellent food quality and variety for buffet.
Good location with shops, supermarkets, bars and restaurants nearby.
Close to the beach (unless you have a buggy, very frustrating to be so close but to have to go the long way due to steps).
Good standard hotel, especially when you see the competition nearby.
Very good environmental policy and set-up.
Mini disco for the kids is great, we're still singing that BUFO song...
The bad points:
The balcony doors are locked by simply pushing them shut. We were horrified to see this as the parents could lock themselves out on the balcony after the kids had gone to bed (or any other time). We had to be incredibly careful not to shut the door fully, but it would be a nightmare if you did so accidentally. Also, by having the door open, the air con would stop, so when the kids were sleeping and the adults enjoying quiet time on the balcony, the apartment was heating up.
Wifi, freely available in the lobby area, but once you stepped outside this area, nothing. It would be great to see them extend it to the seating area outside at least.
Cleanliness; we were a little disappointed with the standard of cleaning throughout the inside of the hotel (outside was fine). Upon arrival in our room, our baby crawled around to explore and when we picked him up his hands and feet were filthy. Not a good sign, floors were swept clean but not washed it seemed. We also saw food on the floors in the dining area that was obviously from the last meal (cornflakes at dinner time, and again the next day). Somebody in a position of responsibility needs to check this job more thoroughly.
Overall we would have no hesitation in recommending the hotel, but certainly think there is room for improvement.