I recently got a Klaas, I think it's a Monolith. A very nice knife which I look forward to putting to frequent use, but it seems Klaas is very much a “you get what you pay for” manufacturer. Their high/high mid end stuff is good, their low end stuff is, well, low end. I think EKA is worth mentioning, they make very nice and clean knives with excellent price/performance. And no list of good slipjoint manufacturers is complete without Victorinox, the gold standard in knife manufacturing consistency.
Just my USD .02.