There does appear to be much contradictory information out there (and within this thread) as you have noted.
It seems that the claims by some, stating that "all HK-serial Dingoos are lesser units" is an unfounded observation. Differing shipped firmware revisions are probably at the root of such rumors. A 4GB Dingoo is a 4GB Dingoo from a basic user functionality point of view. There DO seem to be some functional differences with regard to flashing/unbricking procedures on the newer units (shipped with 2x2GB memory chips and newer firmwares versus the older 1x4GB version), but the whole "issue" here seems to be blown out of proportion. The key would seemingly be to identify which version of the hardware and firmware you have, and to use the suitable tools for these procedures as necessary.
Another unfounded observation seems to be that "All Ebay-sourced Dingoos are inferior". While there are documented reports of some 2GB Dingoos with a smaller battery capacity being sold on Ebay, this does not generally appear to be the rule. As always, the buyer should do due diligence in making sure that they are purchasing what they think they are purchasing. I personally have not seen any of these Chinese Domestic Market Dingoos for sale anywhere.
The whole "Pawed" versus "Unpawed" thing is not a reliable indicator of anything, though it might have meant something a year ago. See Justin's (dingoo-digital-usa) posts on this board for proof of this. The pawprints apparently had to do with branding and distributing of these units more than hardware or function. The presence or lack of pawprints is not a valid identifier. Battery type and memory type IS a valid identifier:
First Gen 4GB Dingoo, Export (Western) Version: 1x4GB memory chip, 3.7v 1700mah Battery / 3.7v 1800mah Battery (Thanks Santino!)
Later 4GB Dingoo, HK & Non-HK Serials: 2x2GB memory chips, 3.7v 1700mah / 3.7v 1800mah Battery
Chinese Domestic 2GB Dingoo, HK Serial (or no serial): 1x2GB or 2x1GB memory chips (?) / 3.7v 1000mah Battery
If anybody knows of or has any revisions to make regarding the basic types above (ie; serial numbering or firmware revisions shipped with them), please speak up!