I love my Jag. I've had V8, and I6 Bimmers, and a supercharged SLK Merc as my 'luxury' sector motors. Very nice indeed and i still like them but i love my Jaguar. It's in a different league altogether. I feel very special driving it and it always gets lots of nice comments. On the subject of service history i agree that OEM is not the be all and end all.
When i was looking for my cat i wanted the 2.5 awd petrol, manual but a 2.0 came up and ticked all the boxes i required (rigidly), and so i brought it on: condition, fsh, sensible mileage, then the petrol and manual criteria as these were non negotiable wants for me.
Take your time, there are loads out there and go try a few. You'll get a better idea of what to look for. Good luck and show us your lovely new cat once you have got it.