Well, I got the DR trimmer and had a few chances to use it on my fairly hilly property. The thing seemed a lot more weight to wrestle up and down some of the inclines than I expected. I was working with weeds that were pretty high even if scrubby and I had to learn how to handle it. After a few runs, and deciding to move horizontally across the steeper slopes, it seems a lot easier.
I am managing to break a lot of strings with it, but this is the first cutting over rough ground, where I find rocks sticking up, broken off branches and stumps, etc, all which will cause an instant break in the blue line. I tried the green thinner stuff but it was no better. I did find that reducing the rpm gives me a chance to find the objects and back off before the string breaks, but I was going through about a string every 10 minutes for a while. Soaking the line in water did not seem to help much, but I plan to give it more than just a couple of hours and see if it gets more pliable. At least the strings are easy to change!
I have to say, the areas that I am cutting would be just about impossible to get except with the DR or a string trimmer. The string trimmers that I tried did not have enough power to cut down the nasty weeds, especially the dry stalky ones. This guy does the job, for sure. I am hoping that it goes a lot smoother the next time I go over the areas that I have cleared of obstacles. I did some trimming of mostly normal grass around some trees and it does a great job on that. Also I found that I can run the thing around my property and end up at the low point, at which time I can bungie the handle down to the trailer hitch on my RTV and tow it back up to the garage with no effort. Still, I wonder if I should have gotten the propelled model. I will have to think on that - there was a pretty big bump in cost.
Thanks for the comments and suggestions!
Frank