Orient Express - Cheap Chinese Rims / Wheels / Forks / Frames / Cranks / Etc

and then contacted me to say one had failed QC checks so they were making a replacement pair

That is refreshingly transparent. I got a wheelset (well, rims, really) from them last year, had a really good experience dealing with them too. They were comparatively quick, better than average at understanding and answering questions, and the final product was exactly what I wanted. They've been performing very well so far too, I'll let my will executors let you know if they do unexpectedly explode ;)

Btw, 'understanding and answering questions' is not even targeted at their knowledge of English, but their reading comprehension. I've found that it is insane how bad some sales people are at just reading what is there, and answering the actual question (and answering all of the actual questions). One British company providing customised sports kit for example stood out as the peak of a negative experience - you'd ask them about two things, they'd answer one of them, but really badly / ambiguously / missing the point... LB on the other hand were pretty to the point, made sure they had understood everything correctly, provided sample images, etc. etc. In that sense, definitely exemplary. Though obviously that is the experience of one single customer with one single purchase!