Hi Pubul57, yes the Carissa Signature is the best 845 i've heard, but i haven't heard too many different 845s. I've heard the Bel Canto i40,and it was very good, but it's been a long time since hearing it, same with the deHavillands. If you are buying new, you should be able to demo one in your system, that would be best.
Regards, Alan