I have one, and it also has stock Android not unlike what's installed on the Nexus devices. I think this is mainly because these OEMs, who are trying to save expense wherever possible, are not going to do anything beyond making what Google provides run on their hardware, and this often involves just copying the reference platform provided by the SoC maker.
(The stories of them arriving with malware are likely from someone further down the chain of distribution installing it, and not the OEM itself.)
The bloatware tends to be installed by wireless carriers and mainline re-branders (e.g. HP), not back-alley Chinese OEMs. If you're buying a no-name tablet and you're not in a Verizon store, it might very well be fairly clean.
(The stories of them arriving with malware are likely from someone further down the chain of distribution installing it, and not the OEM itself.)