The Studio 20's are really nice - I plan to do a nice review with a few friends over real soon. They are very close though IMO. I am looking forward to that review. I auditioned the Studio 20s and was very impressed. I have never heard the RBs by themselves on a good setup. I am very curious how they compare.
I am running a NAD 2600 amp with mine. You can come across one reasonably priced on Audiogon or the bay. It is 150 WPC. However, my favorite amp to drive these speakers is a recently acquired custom built 5 watt tube amp. It is amazing how much sound these speakers put out with so few watts.
Casler's Kitchen and Bar in Fishers, IN has 4 RB-81s hanging from the ceiling in one of their side dining rooms which their are calling their family room. Unfortunately I left my cell phone in my vehicle and could not snap a photo. However in the photos section of their web page you can plainly see them. http://caslers.com/photogallery/index.html