AUDIO NOTE: Their speakers; are they any good in free space?

One question regarding AN speakers. How good are they in free space? I was thinking of buying a second-hand set of AN's for my room approx. 6x4 meters (18x12 ft) big, without an obvious wall to lean speakers against. Would the performance take too big of a hit if I position them in free space? I can't take them home for a test, so I have to rely on forum recommendations. Also, is there a big gap between J and E models? What would be the fair s/h price for these speakers in solid condition?