You wanna know about steel? I'll tell you about steel. Steel is what they made bridges out of in the 1800s. Steel is what they made tanks out of in WWII, and steel is what they made rail road tracks out of until they replaced them with monorails. Steel is good stuff, a man's metal, not some fancypants BS that science dorks dreamed up while sleeping in their bleached lab coats.
4130 is the cheap stuff, but that's only to say it's the butchest frame material of all. It's a little softer than the more expensive steels, and not as strong, so 4130 tubes are a little thicker to compensate. It's no body oil-coated, strutting-in-a-mankini steel, this is a steel that stomps around in jack boots and swings a chainsaw all day. It's thick and tough, and a 4130 frame isn't gonna bend like a flower just because some little rock got in its way or a 260lb dude is mashing on the cranks.
853 is the baddest-assed steel of all. Ordinary steel is weakened when it is welded, but 853 is the Bruce Banner of steels, as it cools after welding it gets both stronger and harder, transforming into the incredible hulk of frames.
Sanko, Reynolds, True Temper, Tange, Nova, and Dedacciai all make different grades of steel tubes for bikes, and like a penthouse full of playboy models, i wouldn't get too hung up over which one i went home with. Different steels can be welded together, so your "853 frame" may only have 1 or 2 853 tubes implanted into it. Trust a good builder to select the right tubes for you and your desires, or try some premarital riding before you settle and "tie the knot." Or read the catalog carefully before you decide which sexy thing you want imported. Geometry and tube selection are far more important than what flavor of steel it is.