Well, the Yeti of the knife world, the XM folders from Rick Hinderer, have received an upgrade. The Gen 4 was on show at this year's USN Gathering and they are finally making their way out into the real world. And when I say that, it is really a bit of an exaggeration, because even now they are not widely available (and I don't anticipate they ever will be). Hinderers are, and always have been, sold directly to military, LEO, and EMS folks. For the rest of us, we have to get them second hand or through dealers of custom knives and that means a HUGE price increase. Typically they go for around $375-$500 depending on model and features when sold to mil/LEO/EMS. For people getting them on the secondary market or through a dealer, they are going for at least $750-$1500.
Here is Neptune's comparison on his site (where he sells whatever Hinderers he can get).
Here is Neptune's video overview of the XM Gen 4 folders. He is, of course, a bit Neptune-ish and by that I mean incredibly informative, fast talking, odd edits, and critical of even the smallest details. He details all of the issues with the Gen 3 XMs before getting to the new knife. But, when it comes to the Gen 4 knife though, he says that it is perfect. And if Neptune says it is perfect, holy shit, it must be great because he can complain about ANYTHING (check on the comparison video between the Sage II and the Sebenza and his correct, but slightly ranty talk about the standoffs around the pivots on both knives). Seriously, this is a video worth watching even if you can never afford a Hinderer. It is a really great knife thoroughly explored by a very knowledgeable knife guy.
If you can't get a Hinderer try the Hinderer collabs with Kershaw/ZT: 551, 560, and 561. They look AWFULLY close to the real Hinderers and ZT makes great stuff. They even have the fancy European next gen steel, Elmax. Really great buys, given the suggested price of $325 translating in to a street price of $200-250. Can't wait until the flipper versions are widely available.
Also something to consider: the soon to arrive LionSpy. With an assortment of high tech ideas (the rotoblock) and interesting parts (such as a replaceable lock bar contact, a steel insert mounted at the end of the lock bar where the lock bar and blade tang interface), this Spydified version of the SR-1 folder from Lion Steel is going to be PRICEY but fits into the bombproof knife category. At a "suggested retail of $459.99" from Spyderco's updated retail pricing list, I would imagine this guy comes in at a $250-350 price point. That is a lot, but it is not quite as expensive as the XM folders.