I have the LMS-332c, great unit, no complaints. I have the external antenna, I had some reception problems by placing the antenna in front of the windshield. Moved it to the back of the boat and I get great reception. I moved the antenna around quite abit in figuring out the reception problems and realized how much antenna placement effects the reception. Bottom line, if you get the internal antenna you won't have the option of moving the antenna! I was unsure of with model to get, 332 or 334, now after the reception issues i'm sure glad I went with the puck!