Our boat is meticulously & professionally maintained and is a higher-end, semi-custom yacht with 10,000 miles under her keel at 2 years old. The bottom line: the more stuff a boat has, the more stuff there is to go wrong.

Now, a working water system is pretty critical but the rest: just happens.
We spent several weeks in the islands this winter without wind instruments because the manufacturer had a "bad batch" of circuit boards & had to replace it... More than once. <img src="http://www.traveltalkonline.com/forums/images/graemlins/Tonguea.gif" alt="" /> Fortunately the wind is fairly consistent down there so it's more an annoyance than a problem.

We had an early charter where a bunch of things went wrong & it did put a big damper on our week, but now that we've been owners for a while, the maintenance I realize that's required to keep everything pristine is STAGGERING. (Thank goodness hubby likes to work on it & we have the ability to have everything done professionally when needed)

I agree that the company's response is the most critical factor... (But as far as the fuel gauge, we just motored & ran the generator for a whole wind-free week & barely used any, so as long as you were filled up when you started, that's probably not too important.)