I will admit that I thought it was going to be a huge cattle boat situation and generally a struggle going in to last year's Cozumel Invasion, but we signed up anyway hoping for the best. To be honest, big groups are something I generally avoid. Janet can't talk me into going on a cruise for anything, as an example.
At the invasion last year I found that while there were a lot of invaders, it was run extremely well! The dinners and other events they put together were a lot of fun, and the dive boats were no more full of folks than any other trip we've been on in Cozumel. We even got in a two tank run down to Devil's Throat on a fast boat.
To be honest we thought the SB Invasion would be a one-time thing last year. We signed up about a week after this year's invasion was released (it took a few days to get our vacations approved) if that tells anyone on the fence how much fun we had last year.
Cardzard and and Roxanne do an amazing job making sure everyone has fun and any issues are resolved. My advice: get off the fence before it's sold out!
You can thank me later.