from the cheaper ones such as Rapport & Official Time to the better one such as Scatola del tempo and Orbita, I have to admit you really get what you paid for.
Few points which I consider as fairly important:
1: Reliability of the winding motor - I've owned my Orbita & Scatola for close to 10years now and they're still working reliably as ever. Needless to say, the Rapport & Official time were long out of commission. (They both failed within the 1st 5yrs of ownership, if I recalled...) Problem on those cheaper ones? Some failed due to cheaper/unrealiable components (motors) and some due to inherent bad design. (certain part wearing out) Looking at some of these brands that you mentioned, I can't help but but wondering if they might just come from the same factory wearing different labels as they all sort of look alike.
Of course one can argue that factoring in the cost, the Scatola/Orbita could easily cost multiple time of the cheaper ones. As such your cost of buying the cheaper one multiple times upon the failure could potentially still be cheaper than owning the more expensive models. For me, a watch winder is not something I want to rotate on a regular basis.
2: Related to above, the realiability and more importantly the noise level of the motors. I used to have one in my bedrooom INSIDE the closet. Even then the winding was clearly audible. As such I need to relocate the winder to my study and it eventually failed anyway.
3: The angle of the winder: Some winder would wind the watch at an angle as opposed to rotating the watch vertically. From my experience, the vertical winding always seem to be more efficient. (i.e. I have some watches that can only be wound at the vertical angle!)
4: Since you're asking about this in a Panerai forum, I would imagine you're into bigger sized watches as well. Do make sure the winder is capable of taking large size watches
5: Last point is something that I have yet to see in the market: Ideally a randomly generated frequency/rotational period to eliminate systematic stress on the winding spring/coil.
I hope this helps!
This message has been edited by Jester on 2011-02-21 21:12:39