I guess I'll be the first to buck the trend. I do enjoy collecting pistols and I have a few from WWII and some other unusual pieces that sit in the safe. However, I never thought of the R9 as a collectable.
To me, this is a tool. A very attractive and artful tool to be sure, but a tool none the less. I just want one of them and I want it in my pocket. I also am much less concerned about how well it looks and very concerned about how well it works.
Regarding which one to collect and which to carry, I would suggest that the one made most recently should be the carry gun. From talking with Karl and others at Rohrbaugh, I learned that they tweak the production guns from time to time making little changes in how the pistols are made to correct problems as they are discovered. The later guns have the more recent tweaks and, to me, this is more important.
Whatever one says about these guns reliability, it has to be admitted that they are at least a bit fussy. Ammo fussy and grip fussy. If the newer guns have tweaks to help reduce the fussyness, then that's the one to have in your pocket.
This is not to say I don't see why others would want to collect these. It's just not for me.
