Marantz PM7000 headphone out

I am looking to buy a pair of headphones to replace the Grado SR60. I'll spare you the decision process, but I want open circumaural and within a budget and it came down to two choices: AKG K601 vs Sennheiser HD595. Now I understand the AKG pretty much needs an amp to sound good, the Senn's may get by without. I do not plan to buy a HP amp right away.
So, does anyone know how good the headphone out of the Marantz PM7000 is? Would it drive the AKG's well enough? It is my understanding that properly amp'd they are slightly superior sound-wise to the Senn's, and I want to know if using them out of the HP out would be good enough to evidence that.
Thank you in advance.