I suspect that there may be some enthusiasts reading this thread who know few facts on the Jaguar but have heard the stories! I have flown it for 20 years in the flight test environment but, sadly, not operationally. I have many flight test stories which could be prised out of me (stores clearances for Operation Granby, LGB Lateral Toss, FLIR/NVG trials, GR1B upgrade etc). However, as a starter I shall try to paint a brief picture of the Jaguar, and as it is just my personal opinion I am sure that there will be some interesting disagreements posted!
The Jaguar is an aircraft that needs to be understood to put it into context with the stories. It has a small, low aspect ratio wing with a high speed aerofoil and small engines which, especially in dry power, develop relatively low thrust. This leads to an optimum sustained turn speed of around 0.85 to 0.9M and a high corner speed (around 430 KIAS at mid sortie weights and low level). Combine this with a relatively low AoA limit, a tendency to depart with large lateral stick inputs at quite modest AoAs and an inertial autorotation mode that is triggered if you roll and push simultaneously, the Jaguar obviously is not an agile low speed combat machine! Nor does it have a high dry power maximum speed, rapid reheated acceleration from low speeds, a high dry power ceiling nor good take-off performance (especially at high OAT). Therefore, it is not surprising the F-4 squadrons were not impressed with the Jaguar as a replacement aircraft!
But, it definitely has its good points. Up to 480 KIAS, you can fly it very low (as evidenced in some of the threads relating to the Omani Jaguars) although at higher speeds it becomes a little oversensitive in pitch. With respect to "operational" low flying its flying qualities are far superior to the Tornado and Phantom (but not as good as the Buccaneer!). It is excellent for tracking in guns and rocket attacks and has a very good Laser Range and Marked Target Seeker system (LRMTS). Also, the maximum speed and g limit with a full weapons load, even at maximum weight, is considerably better than just about all other current RAF attack aircraft. And the nav/attack system has come a long way from the early days of NavWaSS, when it had an 8k computer and a moving map and HSI that froze when you selected weapon aiming, and a 5:1 geared HUD! In 1995, the GR1B became, I believe, the first RAF combat aircraft to have an integrated GPS/IN navigation system and the first RAF single-seat aircraft to carry a laser designator pod (TIALD). This was further developed into its current GR3/3A incarnation incorporating several more RAF "firsts"; a helmet mounted sight, a ground proximity warning system combined with obstacle warning and terrain separation cues in the HUD, and electronic emergency checklists and airfield approach plates on the cockpit multifunction displays. Please note that this is not a commercial for BAES as much of the work (including the whole GR1B upgrade) was not done by them!
But back to the bad news. The Jaguar does not, I believe, have enough pylons for stores carriage. When introduced into RAF service in 1974, there was little thought given to electronic warfare and PGMs were some way off. Therefore, on the four wing pylons and fuselage centreline pylon the Jaguar could carry two 1200 l fuel tanks and four 1000 lb bombs, which was a respectable load. But once it moved into the EW era and the outboard pylons were taken up with a chaff dispenser and active jamming pod, it was left with only one external fuel tank plus four unguided bombs (on tandem beams on the inboard pylons) or two 1000 lb LGBs, or two external fuel tanks plus two unguided bombs or one LGB on the centreline. Or, with a TIALD pod for a self-designation LGB attack, it could carry only one external tank and one LGB. Overall, the weapon load was becoming very small, despite an excellent capability for accurate delivery.
I hope that this has given a little meat to put on the bones of the apocryphal stories. Flight test stories to follow.