The G260 is an amazing regulator and it is one of the few remaining "old school" full size diaphragm with a hard cover and spring button purge that has a seat saver function. Coupled with a Mk 17 Evo (2 now?) I think it the best compromise for travel to any environment. The turret of the Mk 19 and Mk 25 is just not that useful to me for single tank diving and it makes the first stage huge and heavy. And, really, for temperate and tropical, anything but freezing cold, the Mk 11 (now Evo) is all you need. The only thing exposed to seawater in the ambient chamber is a coated stainless steel spring and the ambient diaphragm, it is just not an issue for corrosion or damage from abrasives. And the Mk 11 is small and light and the new Evo version has, depending upon your preference, better hose routing similar to the Mark 17 Evo. Sealing of diaphragm regulators is really only needed when the conditions are extreme cold, well below the temperatures most dive at. For those few who do go under ice or similar extremes, well, yeah, get a fully sealed regulator. Sealing the Mk 11 gives you a Mk 17 and the weight and size difference while not huge is noticeable.
