We did a trip on the Eclipse in 2001. It was great. We spent 1 week on Eclipse, 4 days in Pelileu (Storyboard) , and 4 days in Koror (Caroline's). The time on Eclipse was far superior.
We contacted John (Eclipse owner/captain) through Sam's Tours. He's based at their dock. Sam's is a top-quality operation.
Staying on Eclipse was a lot more like visiting your kooky uncle at his cabin than going to a fancy hotel. It's not a real big boat (we were 3 travellers, plus John and a dive/adventure guide, Jonas), and it's not fancy - no AC, small cabins, etc. But it's got everything you need: food, beer, kayaks, a few books, air tanks & compressor.
The boat was comfortable with that many people. With 4 guests and 2 staff it would have been crowded. The boat has a V-berth that sleeps 2, two single berths in the back, and John sleeps in the galley. There are 2 heads. The cockpit and deck are comfortable. One of our group slept on deck every night it wasn't raining. The boat has a huge sun-shade tarp over the boom most of the time, so there's plenty of shade & rain protection. Climbing the ladder with dive gear on isn't too hard.
A typical day on Eclipse was:
wake up. Morning dive. Come back up out of the water and discover breakfast is ready. Eat breakfast. Motor to another dive spot. 2nd dive. Put away dive gear, hop in kayaks. Kayak through rock islands to rendezvous point with Eclipse. Lunch. 3rd dive. Motor to anchoring spot. Hang out, snorkle, explore the beach. Dinner is Spanish Mackerel (nothing like anything I've ever seen called Mackerel before - really excellent) that we caught that day. Hang out. Go to sleep.
John & Jonas really know their way around the rock islands. They did a great job of getting us to dive sites when the currents were right and no one else was around. Most days we never saw anybody else. They were 100% accomodating of whatever we wanted to do.
John is a funny & eccentric guy. He did drink more beer than the 3 of us combined, and was a little more cavalier about compressor/exhaust safety than I would have been, but we didn't have any problems. He knows his boat well, and is proficient handling it.
Jonas was awesome. He looks like Tarzan & can do most of the same things. Really good divemaster - fun to be with, but serious about safety and dive briefings. One evening he was spearfishing, and wouldn't come out of the water until he caught something. "Ten more minutes," he kept yelling. Finally he caught 3' fish. He held onto a mooring ball with his feet, held the fish out of the water with one hand, and pushed the sharks sharks away with his free hand until we could pick him up. I'm not making this up.
Paying the extra cash for provisioning and having John & Jonas cook was totally worth it (although I expected it would be otherwise). John's not real big on vegetables & balanced diets, but he'll let you pick up whatever you want at the grocery store before you leave Koror.
Diving at Blue Corner, Siaes Tunnel, Blue Hole, and the other wall dives was epic. The diving down at Pelilue (Pelilue Express & Yellow Wall) were also great. German channel was less dramatic, but interesting & different.
snorkeling and kayaking were as good as the diving. Staying on land or one of the big liveaboards doesn't give you as much opportunity for those activities.
Compared to the land-based diving, being on the sailboat was unbelievably better. It's a completely different experience cruising through the rock islands quitely at 3 knots on Eclipse, compared to blasting through at 25 knots in one of Sam's speedboats. And the quiet time anchored in the little coves was really relaxing, peaceful, and unlike anything else I've ever done.
All in all, we were amazed by how beautiful everything in Palau is both above and below the water.
A couple of other notes: don't miss Jellyfish lake - it's the strangest thing you'll ever do. In Koror, the Indian restaurant is the best place to eat. WWII history tour of Pelileu is interesting. Pelileu is really hot, and theire's nothing to do their except dive & hang out. Pelileu divers is a good outfit. Food at Storyboard is good (crab dinner is worth it, lobster isn't, bat soup is kinda gross but a true novelty). A couple of days in Koror is sufficient to get a feel for it. Maybe the road around Babeldaop is finished now, but if not, believe people who tell you 4WD is required, and the maps & signs are worthless (we never found the waterfalls).
We definitely want to go back to Palau and will spend the whole time on Eclipse if we do. But of course, there's Fiji, Tonga, the Solomons, ...
Hope this helps. Let me know if you have other questions. (I did send a review to Undercurrent, but they never printed it...)