Car & Driver tested a Cadillac CTS-V vs a Jaguar XFR vs a Mercedes E63; they pick the Mercedes 1st, the Cadillac 2nd, and the Jaguar 3rd:

All other things being equal, if the CTS-V had been equipped with an [available] automatic transmission like the two other cars here it might have tied the Benz in overall points. How, you ask? A six-speed automatic V we tested in April for CARand DRIVER.com managed the quarter-mile in 12.2 seconds, 0.4 second quicker than both the manual in this comparo and the one from our November 2008 road test. The difference would have tipped the quarter-mile-acceleration score in the Caddy’s favor.

Read more: 2009 Cadillac CTS-V Comparison Tests – Car and Driver.

This probably is the best summary:

Even with the muted soundtrack, our usually home-team-loyal German correspondent quickly deemed the Cadillac to be the sportiest-feeling car of our trio and one that, at $67,345, undercuts the test’s second-priciest Jaguar by more than $12,500. It will cost you about $8000 more than the Jag to start looking at the Mercedes…

Despite the disparate window stickers, everything else—horsepower, weight, terrible fuel economy, even tire width—is nearly identical in this group. Even the acceleration to 100 mph ended up in a three-way tie.

The three cars are very close in mission, performance, and luxury.  The Cadillac manages to achieve it all for $12K – 20K less cash.