I have a PS-22 that I have been using this year. Really nice and easy to find brush piles and easy to tell when it's a fish as hays47 mentioned. Once you look at the screen for a short period it's easy to pick up what everything is and like he said...if it moves...it's a fish. Cast out (even tells you how far) and watch your lure fall in front of the fish. Easy to tell when you are on top of the pile too when vertical jigging or cast and dragging.
I'm thinking of selling the ps-22 and trying the livescope ($$$). The PS22 probably does everything I need it to do, but the livescope just looks prettier. Why do I look at the new stuff?