Proac question

I have been using Proac Studio 250's for over a year now. I am wondering what the difference would be between say my 250's vs the response 1.5's. Has anyone listened to the 250's ?
I've not heard the 250's. The 1.5's I feel are the best in the Proac line IMO. For what they are, they're very well balanced. But, why not try them and see? can always find a buyer for those.