I've been considering them on and off.
The only negatives that I've read about are troubles when backing up...they cause loss of direction.
And...they keep the boat so flat that you can't raise the bow when smashing into waves. So, if your venue is shallow, gentle flats...they are great.
If, however, you have to cross larger wavy waters..... and you like to adjust your trim so that the bow is higher to better cut the waves and keep the spray down, then...not so good.
Since my usage will be split between open lakes and saltwater flats....I am not convinced that I need them yet.