Look at Bobos pocket auto comparison pics. Its a "sticky" thread at the top of this forum.
It shows size and weight comparison of several 9mm autos. The Rohrbaugh is probly the smallest next to the Kel-tecs. The R9 also cost $1K+.
I just bought a Kahr PM9 this week. Its a small gun, esp compared to the 4" XD9 Im used to shooting. I took it apart and cleaned it up last night, finally fired it late this afternoon. I was a little skeptical at first. Id heard its got a tight chamber and action, which it does. Its definitely finicky on how I load it. Im used to Tap, Rack, Bang with the XD. Not so with the Kahr. I dont leave guns laying around fully loaded, so I keep the mags full and just rack the slide. I tried that with the Kahr(manual says dont) and it wouldnt chamber or wouldnt fully return to battery. Lock the slide, insert mag, hit the slide release it slams down tight. I only fired 12rds of Blazer Brass this afternoon, just had to shoot it. No probs at all. Slow fire or rapid, it spat em right out. These lil 9s do have some flip to em. Im still getting used to the DAO and recoil, but the PM9 should serve me well. I need to change the sites out and get a holster. I can front pocket carry in my jeans, but it sticks out of my back pocket. Havent tried dress pants yet.
The only other thing with this gun is, Im a lefty, and a couple times the brass hit me on the right shoulder. Not really a big deal, my XD has done it a couple times too. Just dont want to get down my shirt collar. LOL