Personally, the only benefit I've found is the crowing, which we enjoy. My lead hen served as "look-out" and boss before we had a rooster, and all my hens put themselves in the coop each evening.
My five (original) girls went without a rooster the first 7 months. I bought a pretty one (again, because DH and I like the sound of them) who was around 9 months, and it was a disaster. I kept him separated for a few weeks, and gave it a few weeks once they were together. But he was young, strong, and hormonal, and he wasn't taking no for an answer. I ended up with one hen who'd barely leave the coop housing and another with a bloodied comb (more than once). Egg production went down (I guess due to stress). He went to a farm with LOTS of hens.
We tried again the following year. This time we went with a bantam (d'uccle) who was about 2 yrs. old, known to be mannerly with hens and people. The farm we got him from (for free) told us to just bring him back if he didn't work out. When integration time came, it took all of five minutes of chest bumping for them to accept him. Don't know if it's because he was older, because he had manners (never seen him go after a hen that didn't squat for him when he sidled up to one), or what, but they're fine with him except my big ol BO, who tolerates him, but bosses him around.
I'm just telling you this, because I've found that evidently chicken chemistry does play a role. Some hens will take to one roo, but not another.