How much of a speed difference is made when you balance a prop instead off running it the way it came?

Well the biggest thing is wearing out the bushings in the strut. Much easier to balance than to keep replacing the bushings.

You need to sharpen and balance a prop. Balancing does reduce vibration which can cause stress cracks in the hull and screws to come loose plus premature wear on driveline parts. Sharpening will cut through the water easier, increasing speed and reducing propwalk on boats that have that problem.

If you are running a shaft tube for a solid driveshaft, 1/8", 4mm, or 3/16" you can BEND the shaft with a prop out of balance, or Wear Out the shaft tube, causing the prop to spin in an ever increasing circle, keeping the boat from planing, and letting water in!,,, ask me how I know?,,, Been there, Done that!

What is the best prop balancer out there ? I guess i should ask the easiest to use. (new @ prop balancing)

How much do you want to spend? You can get OK ones from $20.00 and go up to well over a C-note! I use a Robart but Top Flite, Prather, Octura, Grim Racer and the one advertised on that other auction site have some good ones.