Help me pick out a fishfinder

Myself and my fishing buddy have been 'roughing it' for the past year fishing without a depthfinder. I've decided to cave in and buy one, but I'm getting overwhelmed with all the different options and models available.

A little background, we're fishing off of a 12 ft Ouachita, so I don't need a $500 rig that costs more than the boat. I decided against portable because they don't seem to offer the clarity off mounted transducers. In my searches so far I've came across a few options, but can't find any reviews or recommendations as they are all just off of the brand's website. In no particular order these are a few models around what I'm looking to spend

Lowrance Mark 4 $199-

Lowrance Mark 5 $159-

Garmin Echo 301c $219- This one doesn't come with a transducer so it gets put at the bottom of the list.

Originally I was looking at the fishin buddy line from humminbird but decided against portable. I have no brand loyalty, I have heard that customer service for HBird can be a PITA but that's small potatoes right now. Please feel free to recommend any units you have used or seen in the same price range.