I can't answer your question, but you might use a gamut program like Color Think to examine the gamuts of the 2 printers with your preferred paper to see if there are any significant differences.
And, why not stay with Epson? You like the results, the customers like the results, and the fact is that a large % of 7900 users, myself included, run the printers for years without any serious problems. You were one of the few unlucky ones with the unit you have. With a new one you could get extended warranty, also. Just a thought.