We did this tour among three others with Amazing Borneo on Saturday, June 15th. Pickup and drop-off were impeccable, everything was organized smoothly. The weather wasn't that good, and it hadn't been for quite a while, as we were told. So we were made aware of the fact that visibility would be poor right from the start. Which is fine, because that's just nature and you can't control it. We were 10 people on the boat and realized from the start that there were only 4 people who came for snorkeling. The rest came to dive. We've done snorkeling before where we were put together with divers, and those tours usually favored the divers at the expense of those who wanted to snorkel. Meaning that the spots were chosen with regard to what you can see when you dive, not necessarily when you only want to snorkel.
We got the impression that this was the case here,too, as we were informed that we would actually not stop at any of the usual snorkeling spots because of the afore mentioned poor visibility.
So our first stop was at the more protected side of an island, with mainly hard corals and rather few fish. We did spot some unexpected clownfish, so that was cool. We actually found visibility quite good, we've had far, far worse, and we began to wonder whether we couldn't have gone to the more colorful reef side of the island after all. Still, snorkeling there was OK. There were jellyfish in the water, harmless ones, but they had quite the sting and you didn't really see them as they were transparent. So we suggest you wear swim shirts or such. But again, they are harmless.
Time allocated to snorkel was ample compared to other, similar tours taken in different countries, though that might actually be one of the good things that came from being with divers:you have to wait for them, which means more time in the water.
Our second spot was pretty disastrous, and it was almost insolent to sell it as a snorkeling spot. There was mainly dead coral, fish life was almost non-existent. Best thing we saw were a few blue sea stars, a few neon blue swarmfish, that was it. The ocean there was practically empty, if it weren't for the jellyfish, that were far more numerous there... I've never seen the likes of it and we snorkel in almost every holiday. We know what you can potentially spot during snorkeling in TARP, so really, this was soo disappointing. One of the boat crew confirmed our suspicion that that was not normally one of their spots. Incidentally, we were the only boat there... Visibility was not great in the second spot either, but that's not their fault. It was still okay, again, we've had worse.
Snorkeling was pretty well safety-wise. Two of the crew were always in the water with us, bringing safety rings to mark the limits of where you should swim, and to help the snorkelers should they tire in the water.
Lunch was very good, selection of local and western food, drinks had to be paid extra. After lunch, we had about 90 minutes of leisure time on the island, then we came back at around 14:30.

It was an okay trip, but we kinda wish they would have either cancelled it, if they really thought visibility was THAT bad, or tried to switch days, or that they would have tried the nicer spots nonetheless... then again, we're pretty sure that this trip was cut out for the six divers, not for the 4 snorkelers and that we had to contend with diving spots instead of beautiful snorkeling spots. We have another snorkeling trip coming up on June 18th... here's to hoping it will be better.

EDIT: We received very nice feedback from management to our review and were offered compensation for this trip. This goes to show that the company very obviously cares about their clients and shows some awesome customer service. All our other tours booked with this operator were very enjoyable: do take the tour to the Kinabalu Park and Hot Springs, it´s totally worth it, and our guide, Joel, was absolutely awesome. You should give him a serious pay raise! He was very knowledgeable about the plants and flowers of the Kinabalu Park and we had some very nice discussions with him. His english was flawless. The tour was only outdone by the amazing snorkeling on Mengalum Island, which is also totally worth the trip. Do not shy away from this trip because of the many tourists that go there, as the reef spreads around the island and disperses the crowds for snorkeling.

Had a great experience with Amazing Borneo from the start. We had certain time constraints and wanted to do certain things, so they worked with us to stitch together some of the smaller itineraries to come up with one that basically custom for us. Prompt and thorough service, with good advice for where to go, what to do. Once we landed in KK everything was absolutely smooth and seamless. Drivers and guides were where they were supposed to be and when, all very friendly and helpful. We chose the 3star level of hotel for our 8d itinerary. Even in smaller, more remote areas (eg the river lodge) the accommodations were clean, tidy and air conditioned. The meals (predictably) were a bit monotonous, which is to be expected on a tour, however they were always well prepared, and the restaurants were very clean, with attentive service. We had a great vacation. There’s no way we could have done all we did in the time we had without them, and they made it easy to sit back and enjoy all the sights, wildlife and scenery. Would recommend Amazing Borneo without reservation.

Canopy walk was a great one, tho not easy to reach if not physically fit.
Views , especially that of the Mt Kinabalu is another priceless experience.
Accommodation at Pine Resort is another unforgettable one.
Overall a worth trip.