Snorkeling in the winter can be tricky with the high surf. I was at Kua a few days this February, and one of the days only a few people were standing in the water at the shoreline as the surf was nearly reaching the lifeguard shack.
You should always take conditions into consideration. You’re right that the winter months are more apt to get bigger swells and should warrant caution.
Definitely depends on what you want to use it for. Out of the water, I like the newer versions (I have a 7), but I still use my 5 for in water because of how it switches between functions.
