Specific, yet general, balance spring question...

[iwantagmt]

It is my understanding, and firm belief, that a free sprung balance is superior to a balance with a regulator. This belief is supported by the many fine companies that use free sprung balances, like Rolex, Omega, Patek Philippe, FP Journe, AP, etc.

I have read that regulators introduce some positional rate errors, and can be jarred out of position, and can "creep" out of position. My question is how common are these effects seen and what is the rationale for IWC, VC, etc charging premium prices for watches with "index" regulators? Basically, why did rolex spcifically chose to go the free sprung route?Does a swan neck adjustment make any difference?

Thanks!! I am very excited for answers to my curiosity!