I thought about starting a new thread, but I guess it's probably better to add to this one. . . I've been meaning to post some more thoughts on the 521 that I got last week. I posted a couple of pics and comments above, but here's a bit more of a review. . .
First off Bear, I e-mailed you back but I'll repeat the info here for everyone's benefit since you asked here too. . . The 521 is about 8 3/8 inches overall with a blade that's almost exactly 4 inches long. Its my first Mora, so I can't do any side by side photos unfortunately.
I mentioned that I wasn't terribly happy with it in the kitchen and I wanted to elaborate on that a bit. The first thing I did when I got it was to give it a quick wash and then start making dinner. My girlfriend is a vegetarian so I was making a veggie stir fry. The blade shape is probably fine for cutting meat, but when cutting vegetables it seems to work more like a splitting wedge. . . the edge sinks in a bit and then the target basically "splits" the rest of the way through. I was surprised that such a thin bladed knife did this. It's especially noticeable with fairly hard root vegetables like carrots. It just kind of makes it a bit hard to control your cuts, but it does still work alright. I didn't have as much trouble with onions or peppers or broccoli, but just about anything with a full flat grind will still do quite a bit better IMO. The guard didn't get in the way too much, but if I wanted to use it for a lot of food prep I would have gotten the version without the guard.
The next day I carried it to work and used it on some plastic strapping and cardboard. It's light enough that I hardly noticed it on my belt all day and it was a bit handier than the folders I usually use at work, but I had to keep reminding myself to reach for it instead of for the Delica that's always clipped to my pocket. I found it awkward to re-sheath, but that's probably a combination of being used to just slipping a knife back into my pocket and the fact that I needed to move the sheath further back on my belt. On plastic strapping it performed very well. I think it performed better than a brand new utility blade. I was pretty impressed. On plastic wrap and cardboard it also did well, but it wouldn't outperform a flat grind when cutting cardboard.
On Saturday I took it for its first walk in the woods. I had experimented with sheath placement and it was more comfortable to access and re-sheath at about the 4 o'clock position on my belt. I didn't get pics of the fuzz sticks and shavings I made with it because I was busy making fuzz sticks and shavings, but it performed these tasks better than any other knife I've ever used. I used the back of my Opinel to scrape my ferro rod to light the fire, but I've struck a few sparks with the back of the Mora too and it works just fine.
Just a couple more notes and I'll be done. . .
On the Scandi grind. . . I think this is the easiest knife in the world to get a good edge on. It came with a kind of rough, toothy edge but after a touch up with red and green DMT stones this very quickly became about the sharpest knife I've ever owned. I'm not the most skilled sharpener but I think just about anyone could get a Scandi super sharp with very little effort. I haven't had it long enough to comment on edge retention, but it's holding up fine so far with just a couple of very quick touch-ups with the green DMT stone after the day of work and again after the walk on Saturday.
On the sheath. . . Yeah it's cheap, but it just seems to fit with this knife, and it is functional. That having been said, I would like something that left more of the handle exposed. I don't like having to grab the end of the handle with two fingers to draw it, then have to adjust my grip to be able to use it. It has gotten easier with practice, but I'll probably end up buying or making a kydex sheath to replace the stock one, but I'm not in a huge rush to do so. I did notice something interesting that I've never seen comments on before. . . There are indentation on the back of the belt loop that look like they snap onto a button:
And indeed it clips onto the button on a pair of jeans perfectly:
Not a comfortable place to wear a knife, but if you have a jean jacket it may work well clipped onto the button on a pocket or something. I'm guessing that it's designed to fit a piece of clothing that is popular among Sweedish outdoors-men.
Well, now I know what everyone's been talking about. This has got to be not only the best knife I own for the price, but one of the best knives I've ever owned, period. Admittedly, I've mostly owned cheap stuff, but still. . .

I hope this helps anyone who's been thinking about trying their first Mora or other Scandi ground knife.