when we were looking for a trip a few months ago I discovered that the Aggressor was already booked Dec-Mar! So we opted for the Big Blue Explorer for first week in Dec. The Pacific Explorer is the sister ship of the BBE... if they have 4-8 people they use it, if there are 9-18 people booked they use the Big Blue Explorer.
I have been told by friends that the BBE is way better than the Aggressor because there are two chase boats/dive groups rather than all 18 people crammed onto one like the Aggressor... meaning at the dive sites you have smaller group. They time the 2 boats to leave at 10-15 minute intervals or they go to diff sites. Never have a full boat of divers on top of each other.
As far as liveaboards go, this will be our second. We did the Nekton last year and loved it. Waaaay easier than doing land-based diving and also twice as many dives each day are possible. Especially for a place like Palau where the hotels are over an hour away from the dive sites, this is a BIG consideration. Some people have told me 2 dives per day in Palau are fine... but if I am going half-way around the world and spending $$$ for airfare, I want the most bang for my buck. BBE schedule has 4-5 dives per day for 6 days! So if you average out the cost of the trip and # of dives, it is a better deal than land-based. Plus all the meals are included, you just dive, eat, dive, eat, dive, eat, dive, sleep, repeat!
Just my 2cents.
robint
4 months to BBE!