When we first acquired our site, it was very clear (visibility 6-8 feet). At that time, it seemed to ski very fast - hard to slow down and very challenging. Over time, we have stocked several species of fish and gone through a series of steps to control weeds, including grass carp.
The visibility is now about +/- 1 foot. In my opinion, the lake skis much easier with the suspended organics. The feeling is slower, with the ability for the ski to sink in and hold better angle. No science to back it up, but the difference is obvious.