I have both rulers. I have the older version of the Lazy Agle Ruler. I have never used it. It was a gift from my mother. This post reminds me that I should get it out and use it.
I also have the Easy Angle ruler in both the small and large sizes. I use them both all the time. They are wonderful for making Half Square triangles from strips of fabric. But my favorite use for this ruler to to cut my binding strips on an angle because I like my binding pieced on an angle. The ruler nips off that little tip and makes it real easy to line them up for sewing.