I did not mind buying open box or B-stock gears as long as they are in mint condition from the retailor until the most recent purchase. I bought a B-stock S400 Mk ii from Buchardt. Cosmetically it looks like new. One or two pieces of minor accessories were missing but that did not bother me. However, after throwing in at least 150 hours of burn-in, I still felt the bass region is lacking some weight and sometime I heard distortions from treble that I did not hear from my other speakers. I start communicating with Buchardt and the service manager, Daniel, who is very knowledgeable, caring and efficient professional advises S400 Mk ii is a neutral sounding speaker so the bass is not boosted as most of the bookshelfs, they are supposed to be placed a bit closer to the front wall, etc. These are all truthful advices but the aforementioned issues were still outstanding. He is further suspecting one of the treble driver is bad so I did a one-at-a-time listening and found out one of the speaer has issue. Buchardt arranged the return and I repurchase a brand-new pair of S400 Mk ii. Problem is solved. What a wonderful pair of speakers like so many reviewers / users appraise and attest.
My point is you never know what the previous buyer does to the gears. The manufacture will most likely only perform visual inspection when they get the stock returned. Although I had many success buying used equipments, one time snake bite experience like this will make me think twice from now on in buying delicate equipments. In my case, I was saving only 150 euros but the time I invest is enormous. Not worth it.