Thank you for you very helpful replies and comments. Sounds like there are other alternatives to the June Tailor ruler which I will look at. No matter how hard I try, how careful I am, what rules I follow, etc., I can't cut a straight line. My best cuts come when I use 2 3-lb small weights on each end of my ruler, but that is never 100%. Maybe I'll do a little better if I get a "fancy" ruler. It's so frustrating to try and try but still come up with uneven strips and squares.
As far as the log cabin ruler, I believe I will invest in this as I really liked making the log cabin quilt I'm about to finish and would like to make more. I always overcut my pieces so I think this will help in trimming them down.