My old Weed Eater "feather lite" has served me well over the past 20 years. It's only required a new pull string and a couple of spark plugs, but looks like it may need the carb rebuilt on it and the gas cap is leaking, so time to get a new one.
I haven't done any research yet, but would like to get one that starts easy and is a longer, straight shaft as I've got several evergreens that I need to reach under to trim back vines that pop-up from time to time. I also have some spots in my ditches that the previous owner filled with concrete chunks I can't mow over the top off, so I have to trim around them until I can get them broke up. The old one is short enough that I have to bend over slightly, which puts a cramp in my back by the time I finish the yard. I'd also like one that is easy to refill the string on.