OK , I freely admit that I know next to nothing about cars. However I did spend a few years working as a 'trade plater', delivering cars to auction sites, etc. Here are a few entirely personal opinions:
Jags: Lovely cars to drive as long as you don't take a look at the fuel gauge (which actually drops before your eyes!)
Mercs: Look nice but feel 'big and heavy'.
BMW 3 series: Nice, nice , nice! But the 5 series is still far better!
Volvo: I rarely drove Volvos. My recollection of them is that they were pleasurable to drive but not really in the same class as some of the other cars in your list.
Hyundai/Lexus: Insufficient experience to comment.
Saabs: YES! YES! YES! Comfortable, fun, responsive - totally superb!!!
So I'd obviously choose the Saab from your list. However you've not even mentioned the one brand which I'd rank alongside Saab. Where are the Audis?
Chris