I think a true testament to the great crew at Ultimate Crossfit is that I still think very highly of the staff, gym, and athletes at Ultimate even after a relocation moved me out of Charlotte to the west coast. I try to go back when traveling to or through Charlotte - it's that good.
Ultimate continues to offer a true Crossfit training experience with a location and hours that work well for professionals working in the downtown Charlotte area. Having worked out with a private coop Crossfit crew before, I found the staff and clients at Ultimate to be top notch. Everyone is there chasing their own personal bests - just the right balance of pushing each other without being narrowly focused on just elite athletes. Some Crossfit gyms can be a bit intimidating of an atmosphere; Ultimate is unique in helping people new to WODs as well as pushing elite athletes further. Ultimate's owner Lance is a great instructor and fun guy to hang with.
FYI - Ultimate has a sibling relationship with Crossfit Ballantyne. You can't go wrong with either. Also, another Crossfit gym in the Meck area was started by Ultimate alumni. That said, it seems to be the heart of Crossfit around Charlotte.