I noticed many British magazines says XFR has better chassis than either the M5 or E63. In fact, they all select the XFR over either M5 or E63 in comparison tests. But since they are British magazines, maybe they are a little biased (Even though Jaguar is now owned by Tata, it's still a British brand).
American car magazines also think highly of XFR, so it's probably a really good car. I would select the XFR over M5 or E63 because I really like the interior.