I bought a Navico 7000? unit quite a few years ago. It packed in one day just as I was about to depart. I opened it up to have a look and the internals looked very delicate indeed. Don't even think of dropping it.
They are OK for light duty when motoring my ship, but unless things have changed, I would not trust them much for long term use. Mine lasted for about 3 years, and with intermittent use at that.