I'm always puzzled as to why so many think that "denomination" is something so terrible. I think that to deny a denomination is to deny reality.
The Church of God, Anderson, Indiana, has some distinctive beliefs and thus I don't know how they can escape being called a denomination.
They are in-line with other Pentecostal Churches of God, as far as their teachings concerning the Holy Spirit, but they would not agree with other Churches of God on eschatological views. They are not dispensational, for example, and they believe that everything in Revelation has already occurred. I know this because my wife and I were visiting a Church of God, Anderson, for awhile and the pastor gave me a book that explained their beliefs. This pastor told me matter of factly that everything in Revelation has already occurred. They've got a right to be non-dispensational and I don't think that has to make them unorthodox. I was a hard-line dispensational myself for many years and now I see the Mid-Acts and extreme Zionist groups creeping in with bad teaching and dispensationalism has become almost unrecognizable anymore.
It is also my understanding that the Churches of God believe that there are stages of spiritual regeneration. I don't agree with that. The Scriptures teach that we are new creatures in Christ; they do not teach us that we gradually become new creatures in Christ. That's confusing sanctification with regeneration. They are not alone in this error.