I've had mixed results with jake and strutter (actually half strut) decoys. Lots of times a tom will have been beat up by a group of jakes and he'll duck out any time he sees one. I suppose also, some toms are reluctant, just like some people are, to be involved in a fight.
I witnessed a striking manifestation of this one day...I had a tom in front of me, focused on a live hen that I had managed to call in. The hen was rubbing up one side of him and down the other and he was in his glory...Suddenly a group of jakes showed and he folded up and started hightailing it in the opposite direction. I was on him so he didn't make it far but I can tell you, he was scared and was more than willing to surrender his hen and he was no small bird...
I'll use hen decoys all season. Sometimes flat in a breeding position and sometimes feeding or semi alert. That seems to be the most consistent for me...