Looking Garmin's site it looks like all the units I'm familiar with are out of production. The Oregon came out about 2 months after I got my Colorado & it seemed to be a better platform but at the time was major $$$. I'd look for anything that has the capability to flip between a decent satellite image and a marine map/chart. I haven't looked lately, but that was a hard feature to find when i bought mine. Now you can add that to some units as a software upgrade, but you have to search for the sat. maps you want it to load.
I will say that the Garmin units seem to be pretty well built and they still provide software updates for my unit that continue to add small features.
Keep an eye on Black Friday ads - I got mine from West Marine at a rock bottom price plus a rebate on top of the sale price.