Got a little time this morning to open and inspect the new 5.1. "HOLY KNIFE PERFECTION, BATMAN!" This thing is awesome. I have looked it over and so far I simply cannot find what makes it a second. The handle fit is perfect, completely flush, 100 percent along the spine and belly. Yes, I can feel it with the edge of a fingernail in a couple of spots, but you cannot feel it with a fingertip. I will keep looking, but there is absolutely nothing obvious. The edge is as uniform as any I have ever seen, and it's extremely sharp. I didn't spend much time looking over the sheath, but it's very nice, definitely functional in every way.
The balance point appears to be just at, or slightly in front of the first screw. The handle is nicely contoured, and I'm sure I am not knowledgeable enough to offer a meaningful comparison to another handle. Feels good to me.
So, I couldn't be happier. I know, I know, "pics or it didn't happen." I am not set up yet on one of the photo hosting sites, so I will get that going this weekend.