I believe that a used BMW would give you more stability and comfort then a used Jaguar. BMW's are well known to be solidly built and sturdy cars even with high mileage on them, largely it is a personal preference on what type of car someone buys because it all comes down to what exactly they are looking for in a car since BMW and Jaguar offer different things to consumers.
rom my perception I would have to say when it comes to reliability the BMW and the Jaguar should be on par. Given the prices of those vehicles I wouldn't want to pay for either of them. I believe overspending on vehicles is a waste of money. You can buy a reliable vehicle for much less.
This is all opinion and I believe BMW to be better than Jaguar, but Jaguar is a good brand also. BMW just is a more reliable, smoother, and sexier car than Jaguar because they tend to last forever if you treat them with care. But, again, Jaguar is a good car.
A used Jaguar is not more of a sound purchase than a BWM. BMW's have become much more popular over the years and there are many more of them on the road. Whe purchasing a used vehicle you have to think about repairs and where shops are located. With more BMW's there will be more shops to have this vehicle serviced.
No, a used Jaguar would not be a more sound purchase than a BMW, because BMWs are made to least for years. While Jaguars have superior power and performance ability, they are not what most people need for a long-term vehicle for every day living. BMWs are more durable, and they have performance features that are good enough for daily life.