Isn't the comparison should be between the 1-series vs the A-class? Not sure if its being sold locally though but I've seen the new A-class in Europe and interior space is actually quite smart for such a small car.

Now comparing the 1 with the B, I don't think it'll ever drive better than RWD BMW's but in terms of interior space, the B-class is definitely bigger than the 1 or even the 3-series despite its small size.