Some engineers claim that using just an EQ and compressor is enough to master a track properly. There is some truth in that, but really only in the ideal situation of a master. In 9 out of 10 cases you are not going to get away with just using an EQ and compressor. I use an entire chain of plugins that all do a little bit of work in the entire mastering process. By doing so I have full control over the audio file and I can use the power of the plugins which each excel in just a small part of my chain. There are all-in-one mastering plugins, that work ok if you know what you are doing, but I personally am not a fan of using them.