Everything comes down to the implementation at the end of the day. We've had people come into our Meditech 6.x shop from other shops (Cerner, CPSI, MAGIC installs) and comment how much Meditech was an upgrade, and I'd see Epic users complaining about the downgrade all the same.
The entire region's gone up to Epic now thanks to mergers from larger systems, and every site that had everything prior now (especially that crummy little CPSI system) agrees that Epic is now the best thing since sliced bread.
Coming into it though finding out just how much lives in the system... wow. I was amused to see that HR very much lives alongside nurses in the same system (Meditech's HR modules... and an employee portal that quoted copyrights from 1995 from Photodisc!).
To convert this context from medicalese to technese - when a hospital (system) buys an EMR (medical record system), it's like purchasing a very fancy version of "vim" or "emacs"
As all of you know, vanilla vim or emacs can be a very different experience from a polished and tuned up config file version.
So doctors are at the whims of their hospitals high (or often low) quality vim/emacs config, or .rc file of your choice - that's what "implementation" means
Some systems like Kaiser are famous for having super duper special high quality epic configuration, making epic famous for quality, though implementations (vimrc) in other hospitals, most other hospitals, is shite