They're all great units, and they'll all help you catch more fish once you get used to using them.
Right now I have a Vexilar Fl-8se Pro Pack, it's been great the last 2 seasons, but wish I had spent the extra $ on a unit with a "Zoom" feature. Next winter I'll be buying the Humminbird ICE-55. I've seen Marcum's, Lowrance X-67's and Vex's in use, and they all do a great job.