I totally agree, anyone who says that the P-51 was overrated needs a slap.
The P-47 was built as a heavyweight fighter, nothing more, nothing less, it did it's job to the best of it's ability and beyond. However the P-51 could quite literally do any job it was given and do it well, a jack of all trades, master of none. The P-51 was the backbone of the USAAF, and served with more countries worldwide than any other WW2 generation fighter, it also outlived them all, in the guise of the Cavalier which was still in mainline service with the USAF until the late 70's, not a bad achievement for the US built "forgein" fighter that no one wanted. The original Mustang was built to an RAF specification (as a replacement for the underwhelming P-40) which NA did, after various tests with the US army it was modified into the A-36 which did it's job with merit over North Africa, Italy CBI, even destroying 100+ aircraft in air to air combat even though the Allison engine was only designed for low altitude use. Once the stable airframe was married to the RR Merlin they had a real contender. I have said this before but, comparing two fighters against each other all depends on who is using it, where it is being used and for what purpose, the P-51 can satisfy all these catogories as it has been in practically evey situation possible for a fighter, could you say the same for the P-47?