The Rohrbaugh R9 is the best of the best of currently available pocket 9mm's when you want quality with low weight and bulk. I love my PM9, but it's too big, heavy, and blocky for MY pocket. And although the Kahrs are very well made guns (I own 3) the Rohrbaughs' fit and finish are extraordinary.
My R9 has gone through 290 rounds and counting of mixed ammo 115gr - 147gr with no failures. Note there are no restrictions on shooting light bullet weights as in the Kimber Solo, you can practice with cheap ammo with the R9. However the R9 is not rated for +P ammunition.
The sights are far better than the LCP or P3AT (I also own these) but not as good as the Kahrs'. The lack of night sights or white dot options on the R9 is probably it's biggest short fall. Many R9 owners have the sights milled for colored dots.
The recoil is stout but double taps aren't slow, and my 80lb, 12 year old can shoot it just fine, so if it's blowing your arm up 40 degrees you need to do some push ups because this pint-sized little guy is showing you up.
I prefer shooting the PM9, my oldest son (27) prefers the R9 and my little boy (12) doesn't care as long as he gets to shoot with Dad.
For carry, I switched to the R9 from an LCP but still carry the PM9 with tritium sights when I can afford the extra bulk and weight and even a tritium sighted Kahr PM45 in the winter, my wife carries a P9 Covert with night sights year-round in her purse, and my son carries a P3AT in a front pocket holster. (I call him "Ghetto" but he really shoots it well, so I agree with his choice. Shot placement is still king.)
The Kahrs with night sights aren't cheap, nor is the Rohrbaugh, but you get what you pay for. There is no price too high for the safety of my family, so we carry what we want and price is a secondary concern.
Like many other in this thread, I've also been following the Boberg. Whether or not you want a Boberg XR9-S comes down to one question; "Is the extra weight and height over a PM9 worth the longer barrel?" It's a one trick pony. It has a longer barrel with a slightly shorter slide than a Solo or PM9, but it's heavier and taller. The Rohrbaugh R9 is 1/2" smaller in height than the published spec's of the Boberg Shorty and a loaded R9 weighs the same as the unloaded XR9-S. For some of us, size and weight determines if we can carry or not. I hope the Boberg does well, I'd like to see another American manufacturer of quality pocket pistols.
Whatever your choice for self defense, practice, practice, practice, then practice some more. Carry what you shoot and shoot what you carry, a lot...and I hope you never need the skills you've learned.