My wife and I were on the Sky Dancer from Sept. 12-22. Still working on a trip report, and waiting to get my slides back. However, let's just say the trip was AWESOME. The extra few days over the normal 7-day trip meant more time at Wolf and Darwin, and it was well worth it. Saw two whale sharks, one at each Wolf and Darwin. I know this is not a ton, but we were happy to see even one! According to the DMs, the warm water at Wolf/Darwin (about 72 F) has meant less whale sharks this year. From talking to some of the Aggressor folks who were also on a 10-day trip, they saw five whale sharks, though they spent even more days than we did up North, sacrificing the Southern islands.
Though the whale sharks were great, the hammerheads were every bit as impressive, particularly at Wolf. Literally, hundreds of sharks (mostly hammerheads, though some Galapagos and silkies) on EVERY dive at Wolf. On one particularly memorable dive, we were treated to about 90 seconds of non-stop schooling hammerheads. We estimated it was as many as 200 sharks in just that slice of time. Our dive group was simply left speechless.
I haven't been to Cocos, so I can't compare the two. A few divers on the boat had been to both, and felt our diving in the Galapagos had been a bit better. We may have just gotten lucky.
For our Sky Dancer group, we all agreed that the shore trips were every bit as good, important, and interesting as the undersea adventures. You're not missing anything by taking the excursions. Most days, 3-4 dives were offered, with even a couple of days at 5.
Getting to the Galapagos was relatively easy. We flew from the US into Quito, though you can also start at Guayaquil. We then flew via AeroGal for the two-hour trip from Quito to San Cristobal with a stop in Guayaquil (meaning if you start your trip in Guayaquil, you do save a little time). From the little San Cristobal airport, you take a 10-minute bus ride to the main dock and then a 5-minute tender to the boat. Really, fairly easy. As far as luggage, the Sky Dancer folks seem to have it all worked out, because nobody on our boat got charged for excess baggage fees. And believe me, several of us should have been. The boat ride to Wolf/Darwin is fairly long (ours was 16 hours), but since most of it is done overnight, it wasn't bad at all.
Overall, the Galapagos was our best dive trip by far. I haven't even mentioned the other stuff we saw, including red-lipped bat fish, eagle rays, mantas, dolfins, eels, penguins, sea lions, melon-head whales, golden rays, etc. Book early because we had booked ours over a year in advance. When I researched the trip initially, I thought I read that September was the optimal time for whale sharks at the Galapagos, though that was a while ago. Have fun!