The watch seems to be ruggedly constructed and well made. I had no issues with the crown or A and B buttons, as mentioned in a couple other reviews. They are just the standard screw lock type. You have to make sure you have them unscrewed enough to move the buttons in and out far enough to activate, or you will be pushing a slightly moving button with no effect, but they're pretty standard.

Unfortunately, compared to other slide rule watches, everything about the unit as a whole is a bit small. First off, the claim of a "Standard Length" band is somewhat questionable as I have never had a problem with any Casio, Timex, etc. I did have a slight problem with a Bulova once, but it was revealed that somone had "borrowed" a couple links for another watch. The SNA411, however, (with all supplied links) simply will not fit on my "Standard Circumference" wrist. It needs at least two extra links. If your wrist is larger than 8.5" in circumference, plan on the extra $30 and two days of buying extra links and having them installed.  Next is the Slide Rule. Bozhe moy!*Reviewer Pounds head on Desk*
 The outer scale is fine, no problems there. On the inner scale, the time indicators (1:10, 1:20) and so on are adequate, but the calculation indicators that are supposed to be above them proved impossible to read with my nephew's 20/20 vision checked last month. My 40 year old eyes? Not a chance. I really shouldn't have to carry around a magnifying glass to read this. I would estimate that the height of the letters is literally less than half the thickness of a dime. There is plenty of open black space around the numbers, so there seems to be absolutely no real reason to make the lettering this small. The nice clear - high contrast- picture shown on Amazon does not appear to have such a problem. In person, however, outside the photo studio lighting, the real item does. The idea of reading this while aloft in a Cessna 172 is... well, not really a joke - It's just not going to happen! The Tachymeter scale, including associated tick marks also suffers from the same issue, rendering it quite useless. The jeweler I took it to to have more links installed showed me a variety of similar watches, none of which I had any problem reading. But... I didn't buy it from the jeweler...  *NOTE* I can take a picture of the slide rule in macro mode on my Android, and blow it up about double and read it, but, I have an E6-B app on my phone anyway so.... So, in short, when buying one of these, make sure you see it in person first.