You would say, "This doctor is quite something, I must say." --> Your saying that the doctor is very good -->Quite Something means: A remarkable or noteworthy thing or person. -->I must say means: You mean that you admit. Ex: I must say that cop knows how to do his job. Ex: I think that singer is quite something. Hope this helps Tulikah!

Depending on the context and the tone of voice the meaning may be different but most likely this is just a way of saying that the doctor is a good person.