It's possible that a high end production co. can offer consistantly higher quality knife than the average custom maker, but, much as i think a Sebenza is just about unbeatable in the F&F dept, there are a few makers who offer knives that are just as well made, and of course, involving more workmanship and finer detail.
As an example, the Buck/Mayo knife is a very good production knife, in fact, it could be called a semi custom like a Sebenza is also called sometimes, since they are made by teams and there is some hand finishing. But, as nice as the knife is at its price point, a real Mayo TnT absolutely blows it away in every respect, but why should that be the case? Many real Tnts have S30V blades as does the Buck version, both the Buck and real Mayo have Ti handles, the lock, in fact the whole knife is Tom's own design, so, again, why would Tom's real Tnts be clearly a better knife? Well, ill tell you why, he puts a nicer finish on the blades, puts more time into the edge bevels, makes sure the lock is just about perfect, as opposed to production knives where the lock engagement varies to an alarming degree. Makes sure the action is tight and smooth, Buck does this too, but to a far lesser degree. So, the answer is, Tom puts more time, effort and of course he has the skill, to make sure his knives are extremely well made, whereas Buck couldnt possibly acheive this at the price their knife sells at. And i expect this is true across the board with other makers.
There are a few makers who are excellent when it comes to consistantly well made knives and for me, according to my experiences thus far, they are Mayo, Carson, Obenauf, Boguszewski, and JW Smith for folders and Blackwood, Hossom, Dempsey, Denning, Hayes (MS) and most of the Mastersmiths who's knives i have seen. Im sure there are lots of others who's knives i havent yet had the opportunity to handle and maybe other forumites who would add to my list might chime in and do so.
I think of it this way, when i order a Sebenza sight unseen, it is one of a very few knives i am very confident will arrive in perfect functional condition, its like i KNOW the lock will be perfect, i KNOW the blade will be centered, well finished and nicely sharpened, i kNOW the action will be sikly smooth, basically, i KNOW it will be a nearly perfect knife, and yes, i have been disappointed in the past when ordering customs sight unseen from various makers, so, i stick with the few custom makers that in MY personal experience are just about as likely to deliver a knife as well made and flawless as a Sebenza, i hope makers arent offended by this, but honestly, its a high compliment in my mind since i think of a Sebenza as being as close to perfect as a knife can get, at least in terms of quality, precision, consistancy and F&F.
I dont think it has to be a crapshoot IF you choose from among the top makers.