I will be purchasing one of these trimmers fairly soon, but, I ran across a dilemma. These trimmers look to be exactly alike except for a small weight difference amounting to six tenths of a pound. Which trimmer should I purchase? Why would Redmax have two of essentially the same model in their product line? Did the BCZ2600S replace the BCZ2500S? What are the average prices for each model if both models are indeed being sold? I would greatly appreciate any insight that you could give regarding these trimmers. Thank you.