My 2012 did both Jupiter as a Junior and Long Island before Senior Year.
Events were similarly structured. But they had a very different feel given the time of year, # of players attending, # of coaches attending, etc. A lot more coaches and players on Long Island. Most D1 roster spots were known at Jupiter for Seniors, so it was far more of the D3s getting a final look at Seniors. D1s seemed to be getting a first look at the Juniors. At Long Island, we felt that all the schools were highly engaged with the rising Seniors.
Attending in Junior year at Jupiter got my son some exposure, some comfort interacting with college coaches, familiarity with the showcase format, and a good sense of where he fit relative to his peers. Coach contacts he made in Jupiter invited him to two winter camps where he expanded his relationships and did a couple unofficial visits. They also followed my son's Junior year. By the time HF Long Island rolled around, my son's list of schools was pretty solid with schools that had real interest and were fits academically and athletically.