Syd Antin enjoyed his Mustang time:
Wonderful airplane. Great airplane. But for our situation there, not as good as the Spitfire. The reason? The Mustang was built for longer range, it was a heavier aircraft - it could not maneuver as tightly as the Spitfire. The Spitfire was designed and built as a short-range fighter. You gotta remember that all it had to was cross the English Channel and it was in a war zone. The Mustang was designed and built to escort long-range bombers and to defend them in the air. Consequently, it had to have more armament and more fuel capacity, so it was heavier and it couldn't maneuver anywhere near as good as the Spitfire.
The Mustang? Great, I loved that airplane. For our job over there, for combat, we only had to fly a few miles to get to it so we didn't need the long range.
Gordon Levett compares the three combat aircraft flown by the 101:
In mock dog-fights, we concluded that the Messerschmitt could out-climb, out-dive and out-zoom the Spitfire and Mustang. The Spitfire could out-turn the Messerschmitt, the most important manoeuvre in air combat, and both could out-turn the Mustang. The Mustang was the fastest, the Messerschmitt the slowest, though there was not much in it. The Mustang had the best visibility, important for a fighter aircraft, the Messerschmitt the worst. The Spitfire ****pit fitted like a glove, the Messerschmitt like a strait-jacket, the Mustang like a too comfortable armchair. The Spitfire had two 20-mm cannon and four .303-in machine guns (sic; actually, the 101 Squadron Spits had two .50s, not four .303s), the Mustang six 12.7-mm machine guns (i.e. .50-calibre), and the Messerschmitt two 20-mm cannon and two 7.92-mm machine guns (sic; actually two 13.1-mm machine guns) synchronised to fire through the arc of the propeller.... Despite the pros and cons the Spitfire was everyone's first choice. (Levett 1994)
Giddy Lichtman, at least, preferred the Mustang, however (Lichtman, pers. comm.). Aaron Finkel told me that he performed a 360-degree roll in the S-199 once - and it scared him so much, he vowed never to do it again.
During his air combat career, George Lichter spent extensive time in the P-47, the P-51D, the S-199, and the Spitfire LF9. He felt the S-199 flew like ****, saying "You really had to fly it all the time." He loved the Thunderbolt's power and armor and preferred it over the P-51 for combat duty. While he felt the P-51 was perhaps more maneuverable, it had an Achilles heel - its inline engine, which if hit would conk out quickly. The P-51's Merlin engine would give you 30 minutes at the absolute most after being hit. The P-47's radial could take enormous damage and still get you home.
Like many other pilots, Lichter loved flying the Spitfire most of all. "It was an absolute dream. The Thunderbolt was like a truck, and the Spitfire was like a Porsche."
Jack Cohen, too, enjoyed the Spitfire.
Well as far as the Spitfire was concerned, she was just the perfect aeroplane to fly. She had no vices - you did something wrong she'd turn around and say, you know, "don't do it again." Not like some of these American planes. I mean, you know they'd turn round and bite you the second you did something wrong. But the Spit really didn't have any faults - it was like flying a Tiger Moth. Very easy to fly. (Hyde 2000)
Cohen recalls that the Spitfire guns were harmonized to converge at 300 or 400 yards. He also had kind words for the Mustang:
She was fast. If anything slightly faster. But I think the Spit had the edge on her as far as manoeuvrability. Of course, the P-51 had the range. So that's why they could do the long trips even with the bomber boys. She was a very nice plane to fly, but that was only after they put a Merlin engine in it. (Hyde 2000)