Interesting, I've had exactly the opposite experience with it. I find it works heaps better than the WXR 2100 from Rockwell, our fleet has a mix of both fitted. The Honeywell displays useful returns, estimates the tops correctly, while the Rockwell changes its mind every 40NM. It might display red returns at 200Nm, which disappear when you get closer. Alternatively it decides at 40NM that the cloud ahead it previously didn't decide to show is suddenly dangerous and then paints a red fat cell right in front of you.