If I could ever afford one, there's no way I'd take it to the beach. Recently I'v bought a couple of non-working 'tectas, and the reason-beach related corrosion. I could tell by the sand inside, which as we all well know gets into everything. The salt air alone is devastating on metals- resistors especially. With a modern compact circuit board the gaps between circuits are tiny, and a grain of sand or trace of salty dew would be devastating.
I haven't been to the beach for about 5 years now-since I've owned the Infinium, but last summer down the swimming hole at the river I used the GC3080. Although not super-hot, still a versatile machine-especially for the price. I got mine for $150 new. They're $250-300 now. Hard-wired 10" coil and phones.
Perhaps if I sold my 16 detectors, I might have enough for a deposit on a 4500.....? 8.(