I’ve got both the Fishmark 320 & 480. They are both excellent units and work well in deep or shallow water situations. The 480 has just a little better resolution as you would expect with the number of pixels, but you wouldn’t be able to tell much difference without viewing them both at the same time. Hard to beat them for the money.
A buddy has a Garmin 240 and it is also a very good unit. Resolution is maybe not quite as good as a 320 or 480, but plenty good enough for any fishing situation we’ve been in. With most of todays units you can easily read fish, structure, and bottom composition. Target seperation may be slightly better with more pixels and more power, but even that has gotten better with todays units. I’ve never owned a Hummingbird, but from everything I’ve heard, they have more maintenance problems. I’ve never had any with Eagles and I’ve had several. The only reason I’ve ever gotten rid of any is for the better features. I’ve sold all my older units and have at least gotten a little money out of them after replacing.
Gramps