I know a few people whose children go there and are very happy.
When my daughter was entering K, she received a spot at Metrolina, as well as another charter school.
After touring both schools, I decided to go with the other school. I didn't think Metrolina was bad, just not the right fit for my DD. She has a passion for music and the arts, so we opted for a charter that has a whole-child philosophy (one of the Basic School charters in Charlotte), differentiated instruction, and integrates the arts into all aspects of the curriculum.
We just began our 2nd year at the other charter, and so far, we are very happy with our decision. The differentiated instruction was a crucial deciding factor for us, as well as the focus on the arts (but not solely focused on the arts).
If the accelerated, rigorous curriculum is extremely important to you, Metrolina seems to be a good fit. For us, we are happy with the differentiation provided at DD's school, and do enrichment at home to fill in the gaps.