I actually prefer Yamahas to Steinways. Im at a university that has many pianos, so I play on many types frequently. There are 2 Yamaha grands that are the most beautiful I have ever played. The steinway grand is nice, but I don't feel the same sense of perfect control over the dynamics when I play it. There are also 2 upright Yamaha's that are okay. One of them has the nicest touch I have seen. I played on a steinway grand at a recital once, but I felt that the dynamic range between the bass and treble was out of synch. The base notes were much, much louder than the high ones when applying the same amount of force.
I searched for a thread on Steinways because I wanted to see if this problem was as common as it appears to be with Steinways. There are 5 Steinway concert grands at my school, and I have played on all of them, two of them in particular (the two best ones). I have noticed that all of them have this dynamic irregularity - the bass notes are extremely responsive, but the notes around 1-2 octaves above middle C are not very responsive at all. Or, they can be, but you have to be accustomed to the piano to know how to bring out that range. It's quite odd. My piano teacher says she thinks it is a characteristic of Steinways, and another pianist at my school mentioned the same thing. I wonder if there is some sort of logic to designing the pianos this way, because you would think they could have fixed a flaw like this over time - my teacher was speaking on 40 years of experience with Steinways.
That being said - one of the two best Steinways at my school is perfect for Chopin: it has a warm, rich tone and a very responsive dynamic range. And though I love playing Bach on that piano also, the other of the good Steinways seems better for Bach in some ways. It's less responsive dynamically, and the keys are lighter. When I practice on the newer one, the one that's good for Chopin, and then go to the older one, I always notice how much easier it is to play Bach.
In any case, the quality of the Steinway in question most definitely depends on the quality of its maintenance. I'm not very impressed with my school's piano technician at all.