What should I get from SWFA? The 3-15 definitely would work. The 6x seems like not enough magnification to shoot steel to 1,000 yards. Maybe the 10X is enough? Is a 10x going to handicap me at closer distances? When hunting and such, I typically follow the rule of 1-1.5x per 100 yards.
I'd go with the 10x for overall use, but not for a dedicated hunting rifle. I'd go 6x if you are leaning towards hunting.
I've owned multiple of 6x, 10x, 3-15x, and 3-9x. And one 12x. Bought the first in 2008 or 2009.
The magnification will ultimately depend on you. I made the mistake, for many years, believing that others should be able to see targets as well as me. I feel like an idiot now, as I have taken many people shooting mid-to-longrange, and some people really can't see well. And some see really well with unaided vision, but once behind a scope struggle. I used to get frustrated when they couldn't see details through a good scope, but they could see hidden critters with no magnification. Each said that they have weird eyes, but I wasn't listening.
And I know people that can see better than me, and I have better than 20/20 corrected.
The problem with the 6x and 10x is that you can get a reflection off the exterior ocular surface. You have to shade the ocular with your hat or something when that happens. The 3-9x is much better with the reflection back towards your eyeball. I call it a 4-9x though, because it tunnels on 3x.
You can also get bad veiling glare from the 6x and 10x. I had a buck moving at close range once, with the rising sun right behind it, and the view was completely hazed over. I killed it the next day, but that could cost you a shot.
I don't recall getting any reflections off of the 3-15x ocular. And it is excellent for veiling glare - one of the best I think. But, the resolution on the few I had wasn't great. They were really ~12x scopes, as 15x didn't provide any more detail in the image.
ETA - mine were all before SWFA released the new Gen2, and there might be improvements to the latest ones