I personally don't like them, and have removed 2 sets from "preowned" ribs I have bought, simply 'coz I didn't like what they did to the handling.
Having said that, there are numerous bods on here who swear by them.
Whether they improve or reduce your boat's handling & performance depends on numerous different factors like weight & shape of boat, engine, engine trim, prop, etc and most important, what you want the boat to behave like!
Two things that can be said without too much argument are you'll get on the plane that bit quicker, and will loose a knot or two from your top speed because you are dragging more stuff through the water.
If you have a particular handling issue, let us know as someone on here will have encountered it before.