You should really test speakers with your music that your familiar with. The music should also be something that is comparable to what you listen to the speakers with a majority of the time. Take your time. Nuances between speakers are most apparent after listening to one pair for awhile then...
Kefs are known for a wide soundstage. They are brighter than some speakers but I dont think they are brighter than actual live music. Your comment about the resonating cabinet surprised me though. Kef is usually very good about not having that. Try placing a nickel on edge and see if it falls...