As with many things in this hobby, there is a lot of debate and subjectivity concerning power supplies and what sounds "better".
There are debates regarding the sonic benefits of a switching vs. linear vs. battery power supplies and of course, then, the brand of supply.
The Astron is a very high quality, well made power supply.
24 volts will produce more power, but some report that as the power eclipses the 19volt mark, the sound becomes "harder" and "colder". I would argue all those characteristics could vary from system to system.
I think the only way to tell for sure, is to experiment in one's own system.