I've got both the Naos 3200 and 5000. They're both great high-quality mice, but each has its advantages and disadvantages. The ergonomic comfort (excellent!) and the clicking firmness is identical. The Naos uses the (fairly standard) Omron D2FC-N-7N microswitches, found in many, many mice. As you can see in the attached pics, the plungers under the buttons that actuate the microswitches are pretty much right under where your fingertips will be, when gripping the mouse. Clicks are short and crisp. You do not have a "long lever" or a "short lever", so to speak (finger position vs. plunger position along the button, compared to the fulcrum or hinge point), which would give you a higher or lower mechanical advantage, but rather, you actuate the microswitches pretty much directly. Accidental clicks are not issue for me, nor is it fatiguing to use the Naos, as far as I am concerned, they got it just right.
Regarding the sensor, (sigh...), neither one is perfect. If you already have a mousepad preference: The Naos 3200 is better on cloth, but works pretty much the same on a hard mousepad. The Naos 3200 has some prediction, which you may notice; it takes a very slightly exaggerated movement to "unstick" the tracking from a nearly horizontal or nearly vertical movement path. Prediction bothers some people, others couldn't care less; it depends on what you are used to, and your gaming style. If you are a low-sense player, your movements will generally be large enough to always "unstick" the tracking from horizontal or vertical. The Naos 5000 does not have prediction, and that is its main virtue, besides being able to program the LED's to more different colors, and the more advanced macro programming. The Naos 5000 requires a hard mousepad to work well, and that mousepad also needs to be kept immaculately clean. Any lint, hair, dust or whatever bit of loose foreign material gets under the sensor, and sooner or later you will get tracking issues (To be fair, I've found this to be true of pretty much all high dpi mice). The 4-5% acceleration that's been reported is there, but it's not hard to cope with. What I couldn't cope with, was trying to use the Naos 5000 on a cloth pad. I tried the Puretrak Talent, the Steelseries QCK+ and the Mionix Sargas 460; the cloth pads all yielded a somewhat imprecise "floaty" feeling tracking, where the pointer (or crosshairs ;-) ) would move in the right direction, but still didn't seem to quite be following my movements exactly. On a hard pad, both mice are quite usable (slight edge to the 5000, if you keep it clean), but if you want to use a cloth pad, the Naos 3200 is better.