Chinese Linhof/reflex viewer opinions

Hi folks. I was wondering if anyone knows about the the much less expensive chinese Linhof knock-off reflex viewers? It's not so much about whether they are cheaper, but that most of the used linhof (4x5) reflex viewers are usually quite worn, with marked-up mirrors, etc.

Thanks, Paddy

I do not know, but I bet someone knows, so here is a free bump, hope you get your answer, I wonder what the quality is too.

I bought one back in my "chasing silver bullets" days, when I thought it would work better than a piece of cardboard with a 4x5 hole in it.

It works OK as a viewfinder, but, has a lot of barrel distortion.

They're also bigger than they look. The 'dial' is about 2" in diameter, as I recall (It's at home and I'm not).