Cheap Amazon Chinese tube pre amps


Just curious, anyone here ever use one of the many cheap tube pre amps  on Amazon? The reviews are pretty good but not sure if I trust that crowd. For under $100 it makes me want to warm up my system. Rolling tubes is obviously going to be a part of the equation. My system is decent but not high end so I wonder if it might buff off some of the edges from my ss amp
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Vero:  Check this out.  I recently contacted a US dealer about a certain chinese integrated I've been eyeing.  The thing was a grand off.  So I asked questions.  The dealer carries several well-known Chinese brands, but carries other stuff as well, not just Chinese.  The answer I got from him was, and I need to paraphrase here:  "don't even bother. buy American, Japanese and European. "  I think he's trying to dump some of the bad inventory, thus the huge discounts.   This is the dealer saying this to me, not voicing my opinion. 
I've used an APPJ mini2013 every day for the last 6 years in my bedroom system with my Zus.  Love it, and it holds its own when I've hooked up much more expensive amps against it.
i loved my appj. finally sold it awhile back. never a problem so there is that. sold my musical paradise tube amp as well $400 new?. it was a giant killer for the money imo.
Update. I ordered an IFi micro tube 2 for 280$ Will review it when broken in. Likely run it just as a buffer. the reviews were all positive and from some trusted sources imo anyway.