My 2 cents/pennies worth...
If you want a cosseting limousine like silky ride and lots of toys and gadgets in your car don't buy a BMW 3 series; a Mercedes C class (over priced)) or the new Lexus IS probably are better bets. If a classy luxurious interior is the priority the Audi A4 is probably the best bet. If reliability is the priority Lexus again, though any problems on BMW's are generally minor and few (according to various consumer surveys in the UK). Volvo and Saab win for seat and long distance driving comfort, the Saab
9-3 has the most comfortable car seat I've ever sat in. The Jaguar X-Type manages to be a great all rounder that sits somewhere in the middle of this lot and has one of the quietest diesel engines... which is meaningless in the USA
If you want everything else a luxury/executive/premium sports car can offer in a practical package (seats for passengers, trunk for luggage) then it's the 3 series. BMW beats Audi/Mercedes/Jaguar/Saab/Volvo on refinement (it's quiet), performance vs. fuel economy (comparing 5/6 cyclinder engines and diesels if you are in Europe), space (more leg room than the others and equal best trunk/boot space) and of coarse handling and steering responses. The build quality and quality of materials is higher than Toyota/Honda/Subaru. I was able to get the additional equipment I wanted from the options list without spending too much extra, lumbar support essential option for me as seats not quite comfortable enough without it.
The 3 series highlights are the engine and the drive, you have to want great handling as the ride is a touch on the firm side (hence the "limousine like silky ride" comment above) but for me never uncomfortable. There are some that hate the firm ride, so you need to drive it yourself.
BMW is not exactly exclusive but still very desirable and in demand used which still makes them a good buy despite higher prices as they hold their value well... at least in Europe.
There are few horror stories around on the internet about exploding engines etc., but just as many if not more similar problems with Honda / Toyotas etc. No machine is perfect.