I find them better than many other tools including Senuke. Good success rate, all public platform and easy to use. They can be used even for Tier 1 if you use the content the right way or else use for Tier 2
Those authority need not to be relied you. You should know that it is quite easy to manipulate them and make it high artifically. All it matters is your traffic and keyword ranking. They are not only good for you but increased over a period of time. It's all good, relax!