I'm looking at getting an Autotrickler even though my long-used CH 1500 is still going. If I were to do this, do those who are familiar with this product recommend going with the V4, or finding a V3 in the PX? Are the features of the V4 such that it's a much better unit, or is it just minor improvements? I don't usually go with the new hotness, rather I prefer to use what I have til I kill it then upgrade to whatever the best happens to be at the time. With no experience with the Autotrickler, I'm not sure what the 'best' is though.