By good I only mean that over the long-term average qualities of the yogurt aren't trending in any direction.
If you control your temps and follow the exact same handling process for your culture rebatching/mothering, and use a multi-strain, multi-species mix, it is possible without too much hassle. Generally, only would recommend when using on a small scale, because it's tough to throw away a large vat when one could use modern practices and ensure a good result.