I've had a bunch of Real Steel knives. As far as I can tell, they are made by Sanrenmu. They've done some work with designers such as Ostap Hel. They are a reputable brand and you don't have to worry whether the steel stamp is true. While I'm not sure it's "huge",
shane45-1911
is right that their overall quality tends to be a step down from Civivi or Kizer. Their heat treatment isn't always the best either. It's not usually terrible or anything but don't expect the best.
For instance, I sent in some of my knives in 9Cr18Mov for cut testing. The edge performance from Real Steel's 9Cr18Mov was average. That's not a bad thing. However, something to think about with this steel is that the stuff coming from WE (Civivi, Sencut, Ferrum Forge) gets a notably superior heat treatment. It's like the difference between average 420HC and Buck's 420HC with the Bos heat treatment, only from a better starting point. The average edge retention for 9Cr18Mov from companies like Real Steel or Schrade is still a significant step up from 8Cr13Mov.
Based on independent testing, a lot of their 14C28N runs closer to 56HRC. That might sound bad but lots of companies seem to run their Sandvik steels a little soft. For better options, Kershaw and TwoSun have averages closer to 58HRC. I haven't seen any of the Civivi models in 14C28N tested but they seem good.
The bottom line is that if you really like a design from Real Steel, and you have your expectations tempered for a budget knife anyway, don't worry about it. Give it a thorough inspection when you get it. If everything seems okay, go use it! I've had a lot of fun with my Real Steel knives.