I'm interested in buying one of the LF party islands, but had a few questions on which model is the best route. There is a towable, and non-towable version, priced at $400 and $300. I don't plan on pulling this thing around the lake, but I would at least like the option of tying it on to the back of the boat, and possibly pulling it around a cove with the boat in gear, but no faster than just out of idle. Does anyone have any history with either of these two?? Any pro's and con's to either of them?? Is the non-towable pretty sturdy??