Keith, like John and Randy said, the best comparison is with the speakers side by side. Hopefully the salesman will accommodate you on this. I know it's hard, but try to put out of your head the differences in price. Spend some good time with each speaker listening to music you are familiar with and choose accordingly.
In the end, it's about getting a speaker you like! Not which one we'll tell you to get (Axiom, obviously), or which one the salesguy's gonna tell you is better (the most expensive one). The best bet is to see if you can take the Dynaudios or B&Ws home and try them out in your room. Hopefully the store has a return policy and will allow you to do this.
Let us know how things turn out.
