I'm glad that you are looking for the best ELSA
Jay, please attempt to get a demo ride in both aircraft and then decide. If you, like me, are going to spend north of 60K, then the comparative costs of getting a demo ride are relatively small. It may be that one or the other is more attractive to you for purely subjective reasons. I did not fly the R-19, I am told that it is a really good airplane. I think that the RV-12 appears to be a little 'stubbier' than the R-19 but after I took a ride in the RV-12 and 'felt' how wonderfully it flew, the decision was pretty well made for me. The RV-12 is an awesome aircraft.
Incidentally, I really like the removable wings - I thought that I would build a trailer and move my RV-12 between my garage and the airport. It seems that almost no one has used this option except to transport their RV-12 to the airport for finishing construction, etc. I am told that I will probably 'park' my RV-12 inside of a hanger that I share with other airplane owners. I have a great deal of respect for those who already are aircraft owners so I give that advice a great deal of credence.
I suggest that you do more home work as suggested above and also post a 'like' question on the R-19 forums. The answer from those on the R-19 forums might be about the same as mine - to paraphrase others here ' build the aircraft that you want to build'.
You might want to check out the various internet forums such as this VAF and see how much help you might get in answering your questions via the internet. The expertise on the VAF (here) is amazingly thorough and experienced.
Final words tonight - there are over 600 tail kits sold by Vans and over 200 flying RV-12s. Not bad. I have no idea how many 'new' ELSAs there in America but I would bet that a very high percentage of them are Van's RV-12s - for very good reasons I think.
Incidentally, you might want to also check out the 'Sling' - is is a really good looking low wing aircraft too. And they also have a kit for sale. Good hunting!!!