Historical context is necessary to make an evaluation of old cars.
For it’s time it was very competitive. The vehicle for sale here is the V which had 440+ hp and got to 60 in 4.7 seconds, which at that time was very good.
The regular XLR in 2004 got to 60 in 5.9 seconds according to Car and Driver.
Cadillac stakes a claim in the luxury-roadster arena.
www.caranddriver.com
In 2003, Car and Driver tested a Mercedes SL500 which got 0-60 in 5.8 seconds.
From the Archive: Its slippery sheet metal guarantees status with the valet, and it's a shoo-in if the Nobel committee awarded a prize for droptop mechanisms.
www.caranddriver.com
In 2006, Car and Driver tested an XLR-V. It got to 60 in 4.7 seconds.
From the Archive: Cadillac's 443-hp XLR-V brings an impressive blend of refinement and performance.
www.caranddriver.com
In 2003, Car and Driver tested a Mercedes SL55 AMG. It got to 60 in 4.7 seconds.
From the Archive: The SL55 AMG is fast, and 55 percent more powerful than the SL. How fast? There's no simple answer.
www.caranddriver.com
Further, the comparison to the ZR1 of that era is rather meaningless. Many people would choose luxury over added performance. Reviews at the time were extremely positive for the XLR and its luxury content. People only looking for raw speed and power wouldn’t have even looked at cars like the XLR or Mercedes SL.
Traditional luxury roadsters were not focused on performance. Yes, those cars needed strong performance, but smooth linear power delivery was more important than 0-60 or 1/4 mile trap times. Plush leathers, smooth soft rides were, and luxury features were more important for luxury roadsters shoppers than horsepower.