I have a B100R (Made in USA), and a B200R (Made in China).
I'm keeping the 100, but done with the 200. Not necessarily because of USA/China issues.
The "finish" quality (as in the tolex) seams a little cleaner on the USA (100R).
The reason I'm getting rid of the 200 is because of poor design, and that's done in the US. The amp chassis is Aluminum on the 200, whereas plywood on the 100.
The chassis on the 200 chassis vibrates and cannot be stopped. I've returned it twice (as in the one I have now is my 3rd one... yes, trying to give it a fair chance), and tinkered on my own to try and stop vibration to no luck.
That said, other than the tolex tidiness (and it's minimal too), I'd say the USA and China 100's are most likely close in quality.
Also, I've compared a 410HLF USA cab versus a China version... Again, the Tolex tightness seems the main thing visually (again, minimal), but in this case also the USA cab was heavier than the China, and I'm not sure why and not sure if being a tad lighter for the China is necessarily a bad thing for that cab.....
Although not straight apples to apples review for totallyfrozen, I still hope it helps.