I haven't been loading any 300 yet, so I still have a huge learning curve there. However, I have loaded a bunch of 9mm and shotgun shells.
I have an old (circa 1970's) RCBS single stage press. It may be slow by progressive reloader setups, but by George she works and works well. You just can't seem to kill them.
I also like Lee dies.
I don't have a case trimmer yet at all but the camlock Hornady seems to be my current favorite based on concept and expectations.
As for powder dispensing, I have a somewhat unusual setup that I like.
I have a Lee Perfect powder measure that I mounted so I can drop a charge directly into a RCBS scale pan with integrated funnel, which I leave sitting on a Hornady GS-1500 Grain Electronic Scale so I can essentially weigh each charge I drop and this saves me some time and steps in double checking. It just helps me streamline my process some and saves a step, while ensuring each one is spot on.
There are some powders (for subsonic) that I've found, but seems like those that have powders, don't have primers and vise versa. Which causes a big dilemma because I don't want to double up on haz mat charges because seems like shipping and haz mat turns into about $50 from each place.
Unfortunately, I don't have anywhere local to buy powder, so I'm very handicapped there due to the extreme shipping charges. So, I try to find all my powder and primers at the same place and the same time so I don't have to pay a penny more than I have to.