Sounds like you've made a decision, but I'll add my two cents as well.
I've got a non-Rover dog on his first stay with me now; he's a 65-70 pound, 14 month old German Shepherd mix. We had a Meet and Greet in the spring, and everything went well. Owner is a dog training friend of mine, so I felt fairly confident her dogs weren't going to be terrors, and that the information she gave would be solid.
At Drop Off she let me know that he is a big time chewer, and can still be reactive towards people in dark clothes or wearing sunglasses.
I freely admit that I am a bit breed biased about Shepherds---worked at a clinic long enough to see some real fruit loops--so when he showed us his reactivity, I was a little bit more concerned than if, say, a Chihuahua had reacted.
He barks when someone comes in the house, or comes downstairs, or opens the door to my room, or talks upstairs. He's okay with me, but he warily eyes several of the other family members. It's all fear based, and I wouldn't put it past him to bite if he felt threatened enough (which is, of course, what most dogs would do, it's just that his threshold is quite low).
Point being, "wary of men" can wind up being a huge pain depending on your household set-up. Our household is busy, so he goes into barking frenzy multiple times a day. As others have said, I WOULD NOT book this client without a Meet and Greet first, especially since they need someone for 30 days and a dog that big can create serious problems.
Unfortunately in our case, I probably won't be able to book this client again. I don't blame her, and I don't necessarily hate the dog. The biggest issue is that not everyone in our family can do what is necessary to help him overcome his issues while maintaining safety.