Im at the Knox campus and I couldn't be happier about my decision. The campus is brand new and really nice (technology is new). The faculty/staff are amazing and are very supportive as well as receptive to our needs (they really go above and beyond to make our time here enjoyable as well as make sure we have the resources we need). The "established" thing doesn't matter, our campus doesn't have any issues i can pin on that comment. Just like some professors aren't present in Knoxville, some professors aren't present in Harrogate. It's 50/50 so if its an issue for a student it will be an issue on both campuses. For most of the people I know this 50/50 has not been a problem because professors that are not on the campus visit each campus, hold office hours when they can on the other campus, give out their phones numbers and emails for questions even on weekends, some have done online office hour sessions. Example: last semester the Histology professor was based out of Knoxville while the Biochemistry prof was based out of Harrogate. This semester the Immunology professor is based in Knox, but the Physio prof is based out of Harrogate.
Being from here I am sure you know the area is very nice in Knox and you have everything you could ever need. I am not from a rural area so when I interviewed in Harrogate I was concerned about the quality of life in such an isolated area and my options there (food, safety, housing, shopping, coffee shops to study in). For anyone that are concerned about money, I am on loans and I will be fine. Is rent cheaper in Harrogate? Yeah, we pay around $850. Would I be happy in the middle of nowhere though? Nope. So it depends on you. (just to clarify this isn't about nightlife, I have yet to go out in Knoxville and wouldn't make my decision based on that. I don't think anyone would.)
I prefer the Knoxville campus any day of the week. It is safe to say that most if not all the Knox students feel this way.