I have used the Concord Mills location plenty of times. Usually get in the 170-220 kW range. I used this mostly when I had free charging on my way to restaurants in the area. It can be busy at times given it is off Interstate 85. The Starbucks location is pretty new. I would expect it will be OK once you get your Gravity.
I personally haven't had the nightmare charging experience others talk about.
There is also a new Iona station coming to Concord.
IONNA Rechargery coming soon. 16 x 400kW stalls with canopies.
www.plugshare.com