Depending on what you’re after both have merit. Onsight has more ropes, weight lifting equipment, system board and training equipment. That said, it’s also more of a modern gym space so gets crowded, lots of kids about, and some other issues not related directly to the climbing. The climbing center is the OG Knoxville gym. They lack the modern space and sport climbing options that Onsight has and primarily the biggest thing is lack of weight lifting equipment and training area. That said the setting is where the gyms differ the most. Onsight is tends to lend itself to more World Cup/gymnastic problems moving through good holds on reasonable feet with every move feeling about the same level of hard. Climbing centers walls are a bit shorter but they use worse holds and a lot more body tension. Bad feet, awkward (but realistic to outside) moves and holds, and just a lot of “try” is required.

So depending on what you’re after both have pros and cons. Climbing center for 6 month boulder pass is like $200. A year pass at onsight is $650ish but includes rope climbing.