the only drawback that i can think of is it's quite thirsty... that's all
it was a drawback to me b/c at the time i was comparing the S5 against the the 335xi (the latter is more fuel efficient by about 10-15% according to fuel economy.gov). In the end, I weighted the pros and cons of both and decided that the only drawback of the S5 for me was it's higher fuel consumption. Don't get me wrong, i love every other aspect of the S5; and I even placed an order for it. If my wait wasn't so long and an opportunity to take an A5 came up, I would have been driving the S5 now instead of my A5.Can't see how that's a drawback considering all high performance coupes in this market get similar or worse MPG.