Can't say much to the Sightron line, but my SWFAs are the 20x flavor, and also say made in Japan on the bottom of the scope. And I agree on both of your points: tight eyebox and less than stellar optic clarity. Seems counterintuitive but I think the tight eyebox helps with repeatability, when compared to more position-forgiving scopes. And the subpar optic clarity is only a problem right after you've spent time looking through something better. lol.
The SWFA SS line does have some really good things going for it.
For one, they're tough as nails. I fumbled one while taking it off a gun at one point. Dropped it on the concrete floor in my gun room, landed right on the windage turret and it was slighty cockeyed. And that thing still worked like a champ! Tracked correctly and everything. It just had a bit of a physical tight spot in the revolution of the turret. I emailed SWFA and told them I'd dropped it and if their warranty covered stupidity. I figured worth a try to ask, and if they said no I'd just keep it and use it since it was working. Their response, send it in. So, cost me $10-15 to mail it to them and a few weeks later they mailed me.......a brand new scope. They're also springer rated. One shrugged off a couple months of being on a gas rammer RX2 like it was nothing. Still functions perfectly.
So, second good point-excellent warranty.
Third good point-price. Not many $250-300 scopes can be trusted to be turret clickers. I've been cranking on 3 of the 20xs for 4 years and they all track perfectly. (okay, one got replaced a while back, so 4 different ones, two of which have been cranked on for the full 4 years.) They can be 100% trusted to track correctly and the turret mechanism is robust enough to last a good long while.
4th-size. They're not very big and not very heavy, relatively.
5th-reticle. I really like the mil-quad for a functional, non Christmas tree type.
6th-simplicity. I find the fact that you got your choice of 1 magnification, kinda refreshing. There's just not much to fiddle with, which means there's not much to go wrong. No illuminated IR, no side focus (With a cheap throw-lever, I like the rear focus). They're bare bones, and thats a kind of welcome change sometimes.
But yes, tight eyebox and not the greatest glass. And I'll add another one, poor performance in low light conditions. I shoot in the evenings a lot. I can shoot 15 or 20 minutes later into dusk with a Midas Tac, even with it set to 24x, than I can with the 20x SWFA.