and both worked, in actual use.

Since using a line cutter I have yet to have a problem. I'm careful to keep watch but sometimes they're just below the water or hidden by waves/glare. With a line cutter you hear a thud or boom as the float smacks the hull, then you see the float drifting in your wake.

The key with either type is to keep the growth off. I use bottom paint on my cutter and shaft, but leave the 1/8" closest to the sharp edge unpainted. I also don't paint close to the cutlass bearing. It makes cleaning easier. The cutter might not work if growth is allowed to accumulate.