Corona,
Properly configured NTP will not be as convoluted as you seem to make it out to be. I worked at an exchange, and when we needed precise time, we got it down to 300us. If and when we needed more, PTP was being looked into
Precision Time Protocol - Wikipedia, the free encyclopedia
It is not un-deterministic because you do NOT want to alter the clock regularly. There is a reason that it is preferable to slew the clock. Each crystal oscillates differently, and the factors that influence this can be electrical or thermal among others. The way that NTP can correct this is to have a proper drift file as well as a stepping file. Then, the daemon can check values based on the past, even through a reboot.
Normally, on a reboot, a clock would have too much indeterminism to function properly for an exchange system without such tools. The clock would vary wildly for the first few minutes of operation. After the configuration was updated, the machine was usable significantly faster.
This may not be a concern to you, but as modern clusters need to sync'd regularly to function properly, it is hitting more people than it used to.