R22Driver,
For R22/R44 use, to me nothing beats the Garmin GPSIII Pilot-- must be cheap now. We've installed this in R44s on the Cyclic using clamps similar to those used in car radiators attached to the included base. No vibration. Black and white contrast is kewl in broad daylight. Software logic is basically the same as other Garmin products. We've tried installing GPS196 & similar sized Garmins vibration prevents good use. Go with GPSIII-- you won;t regret it in R22.
bogey@6