I purchased most of my R cameras and lenses before 2008, but here is a list and prices back then:
I have a Leica R8, and 2 Leica R6's. I sold my R3.
The R3 had a problem with the batter discharging if left in.
Here's my list of lenses:
28mm F2.8 Elmarit-R
35mm F1.4 Summilux-R
35mm F2.0 Summicron-R
50mm F2 Summicron R
50mm F1.4 Summilux-R
60mm F2.8 Macro-Elmarit-R
90mm F2.0 Sumicron-R
135mm F 2.8 Elmarit-R
You can also easily mount Hasselblad lenses on them.
I mostly prefer to shoot rangefinders, but have found the R's to be great in the studio. I also have the digital back that fits the R8 and R9. The quality is super, and as these decline in price, a reason to consider an R8 or R9.
The reason most people don't talk about them is that they are not for the "trigger happy". You actually have to think about what you are doing.
Almost all of the shots here:
http://www.tangobsas.com/phpAlbum/main.php?cmd=album&var1=Recoleta/
were taken with the R8 and DMR back
The following were taken with the R3 and Flim.
http://www.tangobsas.com/phpAlbum/main.php?cmd=imageview&var1=BsAs_Streets%2FBsAs_Streets_l1011078.jpg
http://www.tangobsas.com/phpAlbum/main.php?cmd=imageview&var1=BsAs_Streets/BsAs_Streets_l1011076.jpg
Almost all of this link was shot with the R and digital back.
http://www.tangobsas.com/phpAlbum/main.php?cmd=album&var1=Roxana/
Also this set was shot with an R and the digital back.
http://www.tangobsas.com/phpAlbum/main.php?cmd=album&var1=Folk_Dancers/
The R6 and R6.2 bodies seem to hold their value better, and I have a preference for more mechanical bodies.
I got involved with the R line when I thought that Leica was never going to make a digital M. If they never had, I might still be shooting only with the R.
Get one body, put as much money in one lens as possible (50mm Summilux is my preference) and spend a couple of months shooting with just that camera and lens.) For a variation, get an adapter, and shoot with a Hasselblad 80mm for some portrait shots.
I feel that the film shots I have taken with the R's closely resemble the type of look I get with the M's.