LS50s and room size

I am very intrigued by the new KEF LS50s. All the wonderful reviews I have been reading have me nearly ready to pull the trigger. My only hesitation is that these will be on my main system and my only experience with speakers of this size are my Audioengine P4s that I use with my computer. They sound fantastic as long as I am sitting right in front of them. From anywhere else, they sound very small. The ls50s would be replacing my old Vandersteens which even though they are outclassed by the p4s in almost every regard, they fill the room with sound, no matter where I am positioned. I guess what I'm asking is if I get up and move around, will the magic disappear? My system is in a smallish room now and I will soon be moving in with the girlfriend where they will have a bit more space, but not much. I would love to demo these in person but the nearest KEF showroom is about three hours away and they are closed on the weekends which is the only time I could even hope to make such a trip.

Also, are there any other speakers I should be looking at? The price of the KEFs are about as high as I am able to go at this time since I will need to get stands as well.