If you're going to price shop you need to make sure you're comparing "apples to apples". The biggest factor for a successful outcome is the surgeon's experience with the technique. That's part of why there are still several popular options at different price points. Other factors are the size of the dog, the owner's post-op expectations for level of performance and properly following the post op care instructions.
Many Veterinarians performing the TPLO are Board Certified members of the American College of Veterinary Surgeons.
https://www.acvs.org//what-is-a-veterinary-surgeon
But, a Veterinarian without advanced surgical training can also take a course, buy the equipment and offer the surgery.
Some facilites have 24hr post op monitoring, care and pain management. At other's your dog may be unattended in the overnight period post-op.
Both options have the potential for a good outcome, but understand where some of the difference in price may come from.