Took the speedboat to Phi Phi Island. The trip itself was fine. One hour by boat each way, 3 different islands, cold drinks and fruit on the boat, a buffet lunch, and a very good/very enthusiastic boat captain/tour guide. So if you want to go to Phi Phi Island, it's a decent option.
HOWEVER: the problem with Adaman is they pack about 35 people into each speedboat. There's nothing inherently wrong with this -- because even if you end up on a smaller boat, you will end up going to many of the same places and it will seem very crowded. The problem is, you have much greater variance in other people's punctuality.
Our trip was marred by 2 such examples:
(1) The van picked up 4 of us at our hotel. At the very next hotel, it was to pick up a family of 5. The family of 5 said they had just woken up, and they would be down in 5 minutes. 30 minutes later, they reappeared. Of course, they were apologetic, etc. etc. etc. -- but c'mon -- 30 minutes? That sucks.
(2) On our visit to "The Beach" island, we all had an hour to hang out on the beach (very nice beach, but pretty crazy crowded with tourists taking selfies). Boat captain tells us that we will have an hour, and the boat will come back, and we all need to get on the boat. Everyone gets on the boat. He counts 33 people. 2 people are missing. He runs out looking for them. 30 minutes later, he returns with them. Of course, they were apologetic, etc. etc. -- but c'mon. 30 minutes? That sucks.
So on our trip to Phi Phi, we spent an hour waiting for other customers. This may or may not happen to you, but for this sole reason, I would recommend going with an outfit that takes fewer people on smaller boats. Your chances of needing to wait for others (for a really long time) is substantially lower.