I will say I have heard same opinions as written above and will also say I tend to be in the same camp as they are as to if I am spending that money just go full custom.
But my limited experience with shooting and watching others shoot 3 different Christensen rifles I have to say they all shot fantastic and with just factory ammo.
Those three rifles impressed me....heck they shot as good as my Tikka’s.

I've never had them NOT take care of a customer who had one that wouldn't clear 1 MOA easily.

I shoot A LOT of rifles and test many rifles. I've had 2 customer rifles in for load work up that simply would not shoot. Christensen Arms did not take care of either one. One was a $5K, 338 Lapua that strung bullets diagonally as the barrel heated up. At 100 yards, I would shoot 3"-4" groups up in a diagonal line. At 200 yards, I couldn't even keep track of which bullet was which the groups were so large. We sent it back twice to them. They sent me a digital print out of a target that had a .97" group, stringing in the same diagonal pattern I had seen. After some discussion and lots of questions they were hesitant to answer, it took them over 30 rounds to get this one group. They sent it back to us after the second time, and said "It met their accuracy guarantee". I told him if you take this stance, I will never recommend a Christensen Arms rifle again, and will always let this story be known. I would have to look up the guy I spoke with, but it was one of the VP's, since we tried to take our problem to the top.

If you let the barrel cool between shots, it would return back to shooting to the first round zero POI. Once the barrel began heating up, something with the carbon fiber wrap was causing the POI to walk up in a diagonal pattern. For a $5,000 338 Lapua, that's not right. For this reason, if a customer brings me a Christensen rifle, I charge a little extra because I know there is a decent chance that I may have a problem with it that will require more range trips and more ammo to work on it. IMO, there are MUCH better options in carbon fiber barrels, like Proof.

Another thing, I don't understand all the hype on the carbon fiber barrels. A #2 sporter weight barrel is lighter than a carbon fiber barrel is. A Bartlein #2B (thicker barrel at 3.2 lbs, or 3 lbs 3.2 oz) is EXACTLY the same weight as a Proof carbon fiber barrel (.308", 26" barrel is 3 lbs 3 oz). If you went up to a #3 contour, the Bartlien steel barrel is 3 lbs 8 oz, and the Proof is 3 lbs 3 oz. I would always want a steel barrel over a carbon fiber barrel, no matter who makes the carbon fiber barrel.

Except for Judd, he’s a scientist expiermenting!

Look at me just following the science

Friends don't let friends buy Christensen Arms...I learned the hard way. I ran across a good deal on a 28 Nosler, talked a buddy into buying it and we did load work up. First trip the range we needed a hammer to open the bolt. It shot 195's extremely well but at 2850...which is about 250-300 fps slower than it should've been. Never could get it up to speed without pressure...tried 2 different powders.

Judd, this is most likely due to the dual extractor plunger (2 of them) on the bolt face. The double extractor plungers have much less solid bolt face for the brass to come back on. This causes more pressure signs on the brass and limits how hot you can load it. I always back my loads down for the dual extractor plunger bolts.