PM sentDepends on what type of competition you're figuring on getting into. The Criterion barrels are perfectly legal in NRA/CMP competition, although a barrel with a 12" twist may not be legal (sorta goes against "as issued"). Where Criterion barrels or other brands are not legal is in Cast Bullet Association military rifle matches. With the CBA it has to be an original GI issue barrel. I tried to get them to change as there are a lot of other milsurps other than the Krag that Criterion makes barrels for, but some of the older management thinks that either finding a new USGI barrel or making the one you have shoot is part of the game.
Obviously, like new Krag barrels aren't going to be easy to come by. Though I don't doubt some old parts supplier has a few somewhere that he's forgotten about.
A Douglas blank long enough to get a 30" Krag barrel out of would be pretty pricey (if that's the length you need) and then you'd have to get it machined to the proper contour, threaded, extractor groove cut, front sight dovetail cut, and finally rear sight holes drilled and tapped. All that is done for you with the Criterion, and all you need to finish the job is to have the front sight brazed or soldered into the dovetail. I used to think about a Douglas barrel myself, until I saw it'd take an extra long blank and a lot of machining.