I own a Cary 303/300 as well as a server which runs through a Benchmark DAC-1 into the same system.
The Cary has lots of adjustability, but the DAC-1 sounds different to me than any of the combos available on the Cary. But ... different will not be better to all ears.
I've found 2 camps of DAC sound - "rounder" and "leaner" (speakers and cartridges, too).
If you prefer the rounder sound of the Cary's onboard DAC to the leaner, more revealing (IMHO) Benchmark, I'm not sure you'll find what you're after. The Cary is really good - of this type. It's plenty revealing, but warmer and will sound more "musical" to some.
OTOH, if you prefer the DAC-1, there's probably a bunch of good choices out there, the DAC-1 certainly among them.
Good Luck
Marty