Dac quality compared to Axon 7?

Hey guys, the only factor that is making me choose the Axon 7 over the OP3 is the dedicated DAC. I was wondering if you guys would be able to tell me if the sound difference would be a deal breaker over the OP3 whilst using headphones? If the OP3 is almost as good as the Axon 7, might as well go for the OP3. Any help appreciated, thanks.

Cheers