Is using underscore suffix for members beneficial?

Question

class C {
 private:
  int member_; // here is the underscore I refer to.
}

This underscore is recommended by Google Style Guide and Geosoft\'s C++

Answer 1

there is one more "style" which suggests declaring class members as below:

class Foo{
    int m_value;
public:
     //...
};

i found it usable. but it is just my point of view.