Colt, LMT, Sabre Defense, CMMG, Bushmaster, and Noveske all use 4150 steel. They all offer chromelined barrels as standard features. If you take Bushmaster out of the list then they all offer 1x7 twist rates and MPI every barrel. Bushmaster does offer 1x7 as an option and batch tests their barrels. IMHO having a chromelined barrel is more important than what type of barrel steel was used. Rust inside of your barrel will wear it out faster than any amount of shooting you do.
Most of the other companies use Wilson barrels. They come standard non-chomelined with a 1x9 twist. For an extra $45-50 you can get a chromelined version.
But by the time you pay extra for the chromelined 4140 barrel you could have purchased a MPI barrel from any of the companies that uses 4150 steel except Colt.
The companies that use 4150 steel also offer quality controls that the other companies don't. According to some engineer/industrial types who have posted on here there is very little difference between the two types of steel. I don't know I'm an end user, but there's a reason that Mil-Spec barrels all seem to be made out of 4150 steel, and that many companies continue to use it even though it is reported to be more expensive.
ETA: I forgot BCM and probably a few other manufacturers who use 4150 steel.