Mike,
The short answer is that all of the companies you mentioned make great cars. All of them (with the possible exception of RUCC) have been in the business a long time and offer great customer service.
ERA would be at the top of my list, along with Kirkham and Shelby. Next would be Midstates, Unique, Johnex and Everette Morrison. RUCC, and FFR would be next in line.
If you peruse the general forum section and visit
www.cobraforum.com, you'll find that this question has been asked many times with many different responses. Good luck, you are starting the process by doing the most important thing....research.
Cheers
Jim