The R-9 is a LOT smaller than the P-11 even though it weighs the same. In fact, the R-9 is just a bit shorter, taller, and wider than the Kel Tec P-32. Onslaught posted a table comparing the R-9, the Kahr PM-9 and the Kel Tec P-32 in an earlier post on this thread. The P-11's specs are:
Technical Specifications
Calibers: 9 x 19 mm Luger
Weight unloaded lbs. 14 oz. 400g
Loaded magazine 6oz. 159g
Length 5.6" 142mm
Height 4.3" 109mm
Width 1" 26mm
Sight radius 4.6" 116mm
Muzzle energy max 400 ftlbs 540J
Capacity 10+1 rounds
Trigger pull 9 lbs 40N
The numbers don't really give you a feel for the differences in size. I have both a P-11 and a P-32, and the P-11 is small, but the P-32 is tiny by comparison.
I'll be a lot of R-9s end up in places where P-11s don't go -- like purses and pockets just like P-32s do now.
The R-9's construction of stainless and aluminum instead of polymer is also a large distinguishing difference.
So, the R-9 is 6+1, while the P-11 is 10+1, and the R-9 is tiny by comparison to the P-11. The R-9 is also going to be considerably more expensive, but I don't see them as direct competitors because the P-11 is an accurate compact CCW, and the R-9 is a mouse gun.