Just got back from a 4-night stay. It was my first time staying on-site at Universal, so I cannot compare to other hotels/experiences, but I had a great stay and would definitely stay again and recommend to others. (Sorry if this is a little long)
Arrived around 1 in the afternoon, check-in was easy and they had a room ready to go. Stayed in a standard 2 queen room with the dining credit. Didn't have any issues with the room size, but there was only two of us so that probably helped. Room was very clean, only bit of damage I noticed was a cracked outlet cover.
The hotel itself is beautiful and we had great experiences at Strong Water, Dhrum Club, and Amatista. Didn't get to use the pool area as much as I would have wanted to, but it was very nice as well. The views of water taxi lagoon, the pool, and the waterfalls on the walk to our room were great.
Had some pretty cool views of Islands of Adventure from the room. Water taxis were extremely convenient, never had to wait more than a couple minutes for one (if at all). The staff was very friendly and helpful, so all in all a really great stay.
A few nitpicks:
I'll echo the sentiments about the barn doors for the bathrooms. They just do not provide any sort of privacy. They look nice, but having a door (and a fan that actually does something) would be better. I can only imagine how much worse this could be with more than 2 people.
And then lastly, we had a couple small problems with staff confusion over the dining credit because I chose at first to not authorize room charging since I was told I could still use my dining credit without authorizing room charges. Well, when we got down to Amatista just a few hours later we were told that they couldn't do the dining credit until room charging was authorized... Tried explaining it to our server but after going round and round in circles, I just told them to go ahead and call the front desk to authorize room charging if it would just save us the confusion the rest of our stay. I had gotten a beer anyways and was going to pay for it with the same card attached to our room. Our server sorted it all out and we were good to go - found out later that I even got the beer covered with the dining credit so there was a silver lining.
Skip forward a couple days, and I was at New Dutch Trading Co. to grab a bagel and a coffee before hitting the parks and I was told by the cashier that they didn't accept the dining credit. Again, I tried to explain but only seemed to confuse her more. I ended up paying cash, but then went to the front desk to ask them for clarification. They told me that the confusion was arising from the dollar symbols they put on room keys that don't have room charging authorized and that it's been going on for a little while, but that in any case the cashiers should at least know to call the front desk in those situations. The girl from the front desk ended up walking down with me to get me a refund which was nice.
Other than those two instances, I ordered room service twice and didn't have any further trouble. But I just figure that should be something they'd have figured out by now since it's been about 3 months that they've been open now.
Aside from those couple of nitpicks, I did really enjoy Sapphire Falls and definitely recommend it!