I love the Pioneers. They are the Humvee of hard-use folders. I like knives of just this size, just enough blade to accomplish about any cutting chore, and no bigger.
The ergonomics of the Pioneers are excellent. The handle is thick and shaped in such a way to lock it firmly in the grip without the use of a bunch of abrasive ridges and serrations. Edge to handle, and tip to handle relationships are excellent. Another benefit of the extremely efficient size of the Pioneer is that the butt of the handle nests into the cup of your palm when gripped saber style, enabling a very efficient transfer of force from the wrist to the blade, completely removing the need for a thumb rasp, er...ramp, of any sort.
The Rolling lock is a good design that will absorb an amazing amount of punishment before releasing. I have a newer Pioneer, a Pioneer II I imagine, that I have beaten mercilessly on the spine with a tree stake, and it will not release. I have an older one though, that will release if you beat it hard enough, long enough. No folder lock is perfect, though the Rolling lock is one of the best.
Another cool thing about the Pioneer, depending on your point of view, is that they are to some extent hand-made, and have a lot of character that way. My new Pioneer came with two very different profiles on the two handle slabs in the guard area. A little judicious filing got them pretty close to matching, but be assured that each Pioneer is going to be a little unique from all the others. I like that myself.
The blade grinds vary also. My older drop point has a nice thin edge, and cuts very efficiently, while the edge on my new clip-point is thicker, and will need some edge angle reduction to cut as well. Blade grinds on both knives are very symetrical, surprisingly so considering how much variation there is in other places.
The bottom line is that the Pioneers are an extremely strong, ergonomic, and efficient folding knife, somewhat hand-made, for a heck of a price. They walk the walk and talk the talk prouder than anything I have handled short of a Sebenza costing twice as much. Huge value in terms of tough cutting tool per dollar. I recommend the drop point, or the swept point. The clip point has the same edge and tip shape as the drop point, so it might as well be called the hump-back instead.