Welcome Wayne, I have a CZ-20 and use it 95% for freshwater work in NH(summer),and cabin fever relief on the coast of Maine in the winter. It's only real shortcoming in freshwater is the lack of sensitivity to small gold. The Tesoro TigerShark, StingRay I or II, HeadHunter Wader/Diver(reportedly based on the 1280)are supposed to be better.
But wading in freshwater that has a great deal of foil chaff, the CZ-20 will ignore the smallest foil whereas my Tesoro Tejon will chatter incessantly. The Tejon will find the smallest gold easily, but be prepared for a very long day if you are in foil-slaw.
I won't go in to how rugged the CZ-20 is, you already know that from having the same case. As Maine saltwater beaches vary wildly in mineralization, the CZ-20 gives you a go almost anywhere anytime option.
It is not absolutely perfect, but very few other machines can go where it can go. I love the VCO pinpoint on the CZ-20, it is a beautiful thing, once you master it in concert with the three tone audio ID, you can ignore most iron.
My CZ-20 has the 8 inch coil which suits my freshwater use better, because I get into heavy nail fields from old wooden docks. But for wide open beach use a 10.5 inch would probably be better, others may be able to offer more info on that.
If you are sticking to freshwater, the 1280 may be a better choice, I have NOT used one so can't speak to that. Use the search link on the top of the page, in the checkboxes select about a 12 week time frame, also select search by username, enter my name, and you should able to see what I am finding lately on Maine beaches. I usually inlcude photos of the trash I find so you can get an idea of what the machine really finds ratio wise.
BarnacleBill