Zerstoerer, the SCP3-416AOMDL-A is their top of the line model. It's a very good unit. I think they're the best value, even though they're a little more costly. You'd need to spend two or three times as much to get a scope that's as good. If you get one, consider getting the 80mm side wheel for it. The focus turret is a bit small and the larger wheel makes it easier to do fine adjustments.
Their 5th generation scopes like the SCP-416AOMDLTS you mention are good scopes for the money. It's their midrange line. About the equivelent of Tasco, but probably a bit more precise and maybe more durable. I don't like their lighted reticle as much, because light spills over a bit and somewhat illuminates the inside of the tube near the reticle. I find that distracting.
Their mini scopes, like the SCP3-M3124MDL2 are good for special purposes and work great for SKSes. They're durable and have good glass, but any time you get into optics that compact, you give up something. In the case of their minis, I notice some edge distortion and they aren't as bright as a full size scope with the same power and diameter. They also have the light spill over issue from the reticle. For a .30-30, it would be more than enough, but if you don't mind a big honkin' scope, I'd go with the SCP3-416AOMDL-A. Be forewarned though, it's a massive scope!
As for Sportsman's Guide scopes. It would probably depend on the model, but I know a lot of their scopes are made by "Famous Maker". Famous Maker makes fairly decent red dot sights and lasers. I haven't knowingly tried any of their magnified optics. They seem to be a few steps down from Leapers in quality from what I've seen.