Not so much about the actual room size but more about the listening distance / triangle size.....In my room I'm sitting appr. 110" away from the speakers in a 10 - 15 % nearfield setup...that works unbelievably well, but also keep in mind that I have the suckers 5 ' off the rear wall, and have 15 ' cathedral ceilings....the minimum I'd work with as I've done in hotel rooms at shows would be 3' off the rear wall, and 75" to the tweeters while tweeter to tweeter of the speakers should then be appr. 82 - 85" apart.....that would be an ideal minimum setup...also, make sure that you're not sitting right in front of the back wall...with this nearfield setup on these Scanspeak drivers you don't have to worry so much about room irregularities either...it just works !!!!
If you don't have that space, then I'd go with the Kismets, as their bass doesn't need the extra room to "breathe"....but if you do, then get ready for an unreal threedimensional experience...man, I love those Berylliums