I just bought that edger.  I have an elec cord one ( the cord is a real pain)  and two of the interchangeable ones that go on the weed whacker power units.  The first interchangeable one I was convinced was dying because the switch was intermittent.  So I bought another power unit..(the top portion that has the battery)  then they came out with a different format, the one they have now, so I had to have that too.  It is a PITA to operate.  You have to bend over, and really concentrate....I have 15,000 sq ft of concrete, in two 100' driveways and a 30 x 40 concrete apron to my garage.  so it took a while....so I bought the one you have pictured.  It is cold and I will not need to edge until late April so I have not been able to use it....what do you think of it?
I do have the scathers, two chainsaws one 18v and one 40v, one 8" trim chain saw that has a hedge trimmer that will go on top, 2 hedge trimmers one 18v and one 40v, a pole saw, a lopper, and one of those hand held trimmers that operate like a hedge trimmer only with 3" head.  So I am pretty well fixed for tree trimming.  Then there are the other 65 ryobi tools...

Mike