I have been on both. The CEXI is much nicer. 2 to a room instead of 4-8, for a maximum of 18 instead of 22 passengers, the 5 below decks rooms have 2 heads between them, The 4 above decks rooms have a head in each, they have Nitrox, they have 4-5 dives/ day; where Blackbeards has 3-4/ day, because there are 3 decks & a larger boat, there is generally more room for everyone (I liked having a little more personal space), the "warm- up surprise" (at least on my cruise) after the night dives was warm towels & hot chocolate (that made the whole trip in my opinion). The CEXI is overall much nicer than Blackbeard's for just a little more money. Don't get me wrong Blackbeard's is a good outfit also (I'm going again with them again this summer), but the CEXI offers more & nicer accommodations than the sail boats. Both outfits were very professional & both offered great service in their own ways. Each trip has its own feel. Blackbeards is rather more adventuresome in ways, but is also more rugged & as it says is "camping at sea", where the CEXI had more to offer. I will also say, even though the outfits have very little, if any control over it, the diving on CEXI was generally better than my Blackbeards cruise. The reefs were in much better condition & there was generally more fauna & flora to see. As for booking, you can always call & find out. Sometimes they have open spots. Of course, they always prefer to go out with a full vessel. Hope that helps you a bit.