In my Tricks of the Trae classes one of the things I teach is how to inch your hand up the ruler for an even distribution of pressure and a consistent cut. This tool renders that advise un-necessary!
Easy release tabs are on each end making attaching an dis-attaching a breeze.
Over time the soft silicon suction cups may accumulate bits of lint or fibers making it lose 'grip'. A quick wash and they adhere as good as new. For smaller square rulers etc, one end may be used to good effect.
If you cut much fabric with rulers more than 4" wide, this could be a very useful tool for you. I find mine a great help for stability and comfort and can highly recommend this tool.