As you said it is personal preference, since marbles are or can be subjective
Any company brand could be extraordinary to collect in my opinion, since all the companies have produced particular or limited marbles, therefore difficult to find.
However, there are marbles of more valuable companies than others, some reasons may be linked to the quality of the same or to have operated for a short time etc.
"Christensen Agate" is the boss, it is a bit like the "Rolex" of watches as I see it, but there are several prestigious brands, such as....MF Christensen, known for its slag, Navarre, also for its slag, Peltier, Akro, Ravenswood and so on
Collect what you like, every company has its own "Ferrari"