My friend and I booked a half day reef snorkeling excursion for our trip to Key West last weekend. We were both so incredibly impressed with everything. The Sebago crew and Captain Morgan - yes, that's accurate and yes, she is totally cool about people cracking a joke about it - were awesome! They were very engaging, truly displayed a passion for what they do, and were very attentive to everyone. Oh - and they were hilarious as well which made for a lot of fun. While we didn't have great visibility - and this is no fault of Sebago as some reviewers have cited - we still enjoyed the catamaran ride and being in warm waters.
Regarding the equipment, it was great. Our gear worked fine, the boat was squeaky clean, and there was great seating options all around. While the catamaran could have easily fit more people, Sebago limits the number of riders (we had about 65 on our excursion) which made for a very pleasant trip. Who wants to be smashed with people?
I would 100% recommend Sebago for your trip.