I found the slotted June Tailor rulers to be fine for cutting strips for bowl making. Otherwise not so good. I have trouble holding a rotary cutter and if you even slightly tilt your cutter then your strips aren't even anymore.
As for other rulers I used to love OmniGrid but as my eyes 'mature' I find I like the Creative Grids more. The colors with the OmniGrid were interfering with seeing the lines.
So, try them out at the store or a quilting venue and see which is easiest for you to use. Try with different colors and patterns of fabrics and see .... literally.
ali