I too, am in the process of prepping for an upcoming dive trip, to Bonaire in mid May 2012 for 5 days of diving. I bought the Divecaddy Gen 2 from Diverightinscuba (love them). I wanted to avoid checking any dive gear into the hold. I am also taking an Olympus EPL3 camera, with housing, dual strobes, tray, arms, and sola 800 focus light. Obviously this aint gonna fit in the DiveCaddy, into which I am already packing a 3mm full wetsuit, my regulator, SS back plate and wing and Tusa Split fins size large (have a curved form) as well as rugged booties and clothes. The alternative was to put all the camera gear in a dedicated camera roll on hard case (not cheap either >$200 or a regular roll-on bag), ensuring the camera is well protected, and sending the Divecaddy into the hold (defeating the purpose of having the Divecaddy2 as a take-on bag) . What I am going to do is put all the camera stuff, with wrist dive computer, and 10" mini laptop in an over-the-shoulder sling bag and take this onboard as the "personal item" together with the Divecaddy and try keep clothing to a minimum in the Spider Bag, thereby avoiding any checked luggage. At worst, I will check the DiveCaddy. So be aware, if you are taking a moderate amount of camera gear, you cannot protect it adequately, let alone fit it in the Divecaddy 2. I also agree with my colleague ScubaERdoc that the double D-rings holding the spider bag, though apparently more durable, is not as efficient as clips.
It takes a while to learn how to optimally use and pack your gear into the Divecaddy, so don't leave this to the last minute. Review the online videos for help. As you can see I am already packing three weeks before I head out to my first trip to Bonaire!