Well, the industry uses a similar bird they mix for the world's top brown egg laying. That said, such a mix is only as good as the parent stock used. My instinct says they are chickens and they will lay very well for you. Health and vigor is almost more important than just a breed reputation. I have some of the best pure bred birds on the planet. I enjoy them. I have also enjoyed some mixes over the years that were great layers.
For starting out in this hobby, they'll do just fine. Practice your skills, learn, love and enjoy.