EVERY ANSWER IS WRONG HERE...
First of all, Steinway Uprights aren't the best pianos. They are only average because Steinway spend the majority of they resources developing their concert grand instruments. The Steinway upright is expensive and if you want to get a Steinway, get a grand.
Yamaha - They are okay. In ten years, when the wood tries, the sound becomes very metallic and difficult to take. The action gets very loose and worn on a Yamaha quickly. Of course their are exceptions.
Baldwins - The war horses of uprights. These are great instruments because they last. Not the most attractive, pretty plain, pretty square looking uprights but will serve the job.
Kawai - Probably the best upright only because they have three working pedals. On all other uprights, the middle pedal does not hold the note "sostenuto". It's only an apartment pedal which drops a felt over the hammers to dampen the sound. The Kawai though, has an actual working sostenuto middle pedal. The action is firm and lasts on a Kawai.
Now one has to consider tone, type of action, and sound. I suggest that you try a number of different pianos and see which one is best for you. You don't buy a piano just on the make, you have to play them, see which one you like and which one suits you. Also, you have to consider the costs, because some cost a lot more than others. Don't buy Steinway unless you get a grand because paying $3500 extra for a Steinway upright over a Baldwin is ridiulous and a complete waste of money.