Interesting. Hadn't heard of that one. I bet it will last well. No potentiometers or rheostats to wear out. They don't give details other than calling it "magneto-resistive," which to me sounds like it's a variable inductor or a Hall-effect affair. Potentiometers of any sort are a royal pain when they get a little worn.
The early pot used in the A model referenced in this thread isn't too bad. It's a wire-wound model that doesn't fail at too great a rate, but still not awesome. However, the unit spec'ed for the S model I have is a carbon film unit that fails at great rate, especially for aircraft kept outside. (Wire-wound models fail at a slightly greater rate outside, as well.) The reason is the elements, but not the ones you'd think. It's not sun, it's not rain, it's not cold, it's not heat. It's wind. Even small breezes move the plane when tied down, causing sloshing in the tank and small wiper movements. It's especially bad for aircraft like mine, which, because of club rules, is automatically fueled to about the same level after every flight. The same little spot that corresponds to filled to the tabs gets wiped incessantly all day, every day. The wire wound models can mostly put up with this abuse, failing slowly. The film ones get opens right at these locations. Not open end-to-end, as the edges of the film continue to conduct, but just under the wiper. This also screws with the calibration. And Cessna is charging over $1000 each for them! There was one guy doing repairs on these units, but he passed away, unfortunately.
The CiES units are amazing. They're mechanical porn. They're as impressive in person, or rather more so, than they are in the pictures. Especially if you have the stock unit in your other hand: it's just night and day. The CiES unit is completely sealed, anodized aluminum construction, unlike the stock unit that has an open frame and the bits are all washed in gasoline. The float arm is nothing more than float, the pivot, and a permanent magnet. There's basically nothing to go wrong on the wet side. The sensor is buried in aluminum housing from the outside, then completely potted with only a three wire pigtail sticking out. (And, yeah, that third wire is what causes all the extra expense to get one installed, since it's the power wire.) The outside is basically also impervious to anything. The packages comes with a very nice gasket, which Cessna charges extra for.
This is the fuel gauge I use:
http://www.aerospacelogic.com/index.php?dispatch=products.view&product_id=249 I've heard the CiES can also be adapted to stock, but in my case, the stock unit had failed in my plane (the needle fell off the gauge! how the hell does that happen!), that was a moot point. It can also feed any of the engine monitors.
