The fusee-chain solution is not only super-expensive and exotic, but exceptionally difficult to service. It's pretty much relegated to watches with a $100k+ price tag, without any other complications. At least, that is what Lange charged for the fusee-chain Richard Lange. The original 5001 movement was a classic slow-beat movement, at 18k beats per hour. When they changed to a screwed balance, they sped it up to 21.6k beats per hour--a little bit faster, but still slow compared to the standard 28.8 beats per hour. The magnified effect of beat error is a theoretical issue, but I'm not sure it matters in real-life usage. Precision will be exponentially more influenced by how you keep your watch wound.