Yakima Questions Rail Grabber Vs Low Rider Towers

I guess I need to get some Rail Grabber or Low Rider Towers to fit my new ride any body have any experience or any spares?
Whats the difference, which is taller?

Low rider towers are a little taller.  I had them on my 04' grand cherokee before I sold it.  They're great and easy to install/adjust.  The rail grabbers are for cars with a very low rail system like an Audi a4 avant with side rails. 

I actually like the look of low riders.  Just my 2 cent.