I also auditioned the RM 40 and VR-4 jr recently at Dynamic Sound (probably the dealer in DC referred to above). I would say the biggest differences were in three areas: (1) RM 40s had noticably better "you are there" presence and ability to resolve detail. An example would be hearing a guitarist's fingers scraping on the guitar strings. The ribbon drivers just unmask a tremendous amount of detail. That is not to say that the VR-4 jr's were defficient in that respect - just not as stunningly clear; (2) RM 40's had greater dynamic range; (3) VR-4 jr's were far superior if you're interested in being insensitive to listening position. RM 40's have about an 18 inch vertical sweet spot, if you get above or below that, you miss the best part of the highs. No different with any other ribbon drivers. VR-4 jr's had surprisingly good low bass response for such a relatively small enclosure - although I didn't really test their ability to hold up at high volumes and low frequencies. BTW, I would recommend anyone in the DC area to check out Lucius at Dynamic Sound, he is an extremely gracious host and very knowledgeable.