There are a few reasons I am not in the habit of recommending this. The
first is that the utility I have seen most often to do this is spyware.
Conversely, spyware has an ad budget, so users are perhaps more likely to
find such a widget than some of the freeware that is available. Also, I have
seen utilities like this consume otherwise useful and nontrivial amounts of
memory.
My suspicion is, and I admit I have not researched this, that Windows
services are probably reasonably well optimized to use minimal resources
when they are performing tasks and when they are idle. Also, I am not
entirely clear on this point, but doesn't the NTP RFC have the client track
its own clock drift, and determine how often it needs to resynch, in order
to stay reasonably accurate? Furthermore, I would expect Windows to be
somewhat aware of what it is doing in having the clock either move forward
if slow or slow down if fast, to avoid anomalies of time-based tasks being
unable to perform as expected.
Given the available choices, as much as I admire those who solve problems
and then make those solutions available, my preference is: trust Microsoft.