Yes Rubicon Express is out of business.
It honestly depends, what are you looking for, some kits offer better ride, some offer better performance, some companies will stand behind their product while others tell you to pound sand when things break.
Next to Rubicon Express, I have always been impressed with BDS, (leaf spings) ride it a little stiff, great performance and durability offroad, and when I bent a spring, they sent me a new one no questions asked... Pro comp on the other hand did not.