The Automax is Chinese and overpriced. I have heard both good and bad about them , mostly that they are cheap and not worth it. The Whites are better but they too have had many problems. The new 140MM is better than the 120. I would suggest the Vibraprobe as a very good probe. I have not experienced or heard anything bad about them.
I have the bullseye 140mm and I agree cuts the digging time around 50%. I have had no problems with it yet. It started to rain hard on me once and I was pinpointing with it. Didnt effect it but I wouldnt advise you to get it wet.