You have to take every car maker with a grain of salt.
Sure you don't want to move from a BMW to... like a Nissan Sentra, but if its a Nissan GTR, well, thats a huge difference.
Every car maker has good things about them, and bad things. Its always a tradeoff for power vs looks vs reliability etc.
you cannot say you are going to commit to a car maker based solely on ONE car. Have you ever drove an M5 or M6? what if they were total crap? Would you still be loyal to BMW even if every one BMW was awful and the 3 series is great? (I know the M5 and M6 are awesome! no worries there, and think other BMW models are good as well)
Its all about the particular car. Sure the "brand" is great, but the actual model of car means more.
Would you choose a bmw or nissan? it is easy to say BMW, but what if the actual car choices were a 1980 3 series, or a 2013 GTR? Still be brand loyal then?
With all that said, I love BMW, and do consider their cars higher quality and more suited toward my need for a car than other brands, but this is just a GENERAL statement.
I will always evaluate each car model vs. another and not solely on the brand. I do think BMW makes a superb car and will always consider a BMW in the future, but will not just blindy by a BMW because of the Roudel on the front.