I go there pretty regularly when to lazy to make the tow down to ocean. It can get crowded at peak times on weekends. Definitely are some times when I'm not comfortable letting my 6 year old in the tube because of the traffic around but its not horrible all the time.
Ned's right about a good chop getting worked up in the afternoon from all the traffic.
I much prefer going down to Atlantic Highlands and fishing but for a short trip its pretty convenient for me (about 25 miles) and I wouldnt not go because of the crowds.