Recogntion Guide
Differentiating between Dennou Keisatsu Cybercop, Power Force and their knockoffs
Finding Power Force figures on eBay is pretty easy, there is almost always one or two sealed figures and several “much loved” figures available. Dennou Keisatsu Cybercop figures are more rare, only showing up once or twice a year on the english-language site, and those are usually the home video re-releases. The chrome knockoffs appear regularly in bulk lots, often mis-identified as Power Rangers figures, as well as occasional sealed examples.


Recognizing the loose figures
The first thing to remember is that both Dennou Keisatsu Cybercop and Power Force retained the same color scheme for all releases. There is only one knockoff that I'm aware of that came in the original colors and, according to the report, those were molded in lower quality plastic. Any alternate color schemes, including chrome, are knockoffs. The only official release that contained chrome was the Chrome Chamber weapon set and the only uncolored figure was the clear “stealth” Jupiter-Bit DVD re-release.
The original 1988 Dennou Keisatsu Cybercop figures had raised copyright text on their buttocks, Power Force and the reissues had a raised flat area on the buttocks where the copyright text was painted:

For the Dennou Keisatsu Cybercop Reissues, the painted text of the copyright changed back to match the originals but with the addition of 1988 beside the ©.
In the Power Force section of this site there are comparisons between those releases and the originals:
The 1998 Dennou Keisatsu Cybercop reissues are nearly identical to Power Force except for two things; the Black Chambers now have a ZAC logo on the front of the chamber and the details on the figures that were painted on for Power Force are decals again.
The knockoff’s buttocks resemble the original Dennou Keisatsu Cybercop figrues with the raised text removed. Power Bots, Metal Robot, and some examples of Power Robot have a "©1994 Trendmasters, Inc. Made in Taiwan" sticker on the figure’s leg:

Some Power Robot figures have both the Trendmasters copyrignt and a "Made in Taiwan" sticker, some have just the second.

Black Chambers
Most of the Black Chambers that you see on eBay in the US are from Power Force, as indicated by the factory-applied, full-color ZAP logo in the center of the front panel. There are only two knockoffs that I know of that came with Black Chambers, the Armor Removed figures (which feature ZAP logos as well) and Captain Power (which includes lower-quality versions of the original decals).
Recognizing sealed examples
The original Dennou Keisatsu Cybercop figures were released in two editions; STD which only included the figure and a "deluxe" version which also included their signature weapon. Both of these editions had windows that displayed the figure wearing their three-part torso armor.
Power Force and the Dennou Keisatsu Cybercop reissues came in very similar window boxes that displayed both the figure (wearing the two-part painted torso armor) and their signature weapon. The boxes for the Dennou Keisatsu Cybercop reissues are noticably smaller than the ones for Power Force.
There was one set of Dennou Keisatsu Cybercop knockoffs that replicated the original packaging, both STD and deluxe versions, but can be quickly recognized by the fact that the figures are not packaged wearing their torso armor. If opened, you would see that the two-part painted torso armor and Black Chambers (with ZAC logos) are sealed on the card inside the box. Also, these figures are like the DVD reissues and Power Force and do not include the extra piece of chest armor. Even the STD labeled boxes in this line contained Black Chambers.