The case was litigated by our very own Tom Bartee, and he has this to say about the decision:
Back in 2006, the Tenth Circuit declared that sentences within a correctly calculated Guidelines range are entitled to a presumption of reasonableness. This case, United States v. Kristl, predated the Supreme Court's decision in Rita v. United States, which is the decision in which the Supreme Court announced that courts of appeals may -- but need not -- apply a presumption of reasonableness to within-Guidelines range sentences. Two points about the presumption, one possibly helpful and one probably not.
First (and unhelpfully), Kristl’s statement about the presumption was pure dicta. The sole issue in Kristl was whether the district court properly calculated Kristl’s criminal history. This is nothing more than an issue of procedural reasonableness. The appellate presumption of reasonableness applies only to substantive reasonableness challenges of within-range sentences. Although dicta is not controlling precedent, later Tenth Circuit decisions adopted the Kristl dicta and applied it where it matters, so the presumption now carries the imprimatur of precedent.
Second (and possibly helpful), it may be an open question in the Tenth Circuit whether the presumption actually applies to all within-Guidelines-range sentences, and in particular, to sentences imposed under the flawed childpornography guideline. In Morain, the Court pointedly avoided answering this question. The Court quoted Kristl for the proposition that “[w]e have held ‘a sentence that is properly calculated under the Guidelines is entitled to a rebuttable presumption of reasonableness.’” But the Court followed this with a quote from the Supreme Court's decision in Gall v. United States, and the Court italicized an important qualification to Kristl’s broad statement: “If the sentence is within the Guidelines range, the appellate court may, but is not required to, apply a presumption of reasonableness.” The Court proceeded under the assumption that it could disregard the presumption. As you probably guessed, though, it found the sentence substantively reasonable nonetheless.
Despite the outcome in Morain, it may be worth attacking the presumption when applied to flawed guidelines, such as those governing child pornography, drugs, and career offenders.