I'll admit, a large refugium is probably better if culturing copepods is the primary purpose....however, if culturing pods is the primary goal, there are better ways to do it than with a refugium that will give you far denser pod colonies than just running a fuge.
At the end of the day refugia and scrubbers have their benefits and setbacks. Cost will be a wash. Appropriately sized spaced for either will be something to consider, and the up front cost of a quality refugium light vs a quality scrubber will be comparable.
Scrubbers will result in some yellowing of the water from the hair algae they grow, and likely require the use of activated carbon in tandem with them to reduce those compounds. Chaeto will require supplementing other elements in the water to keep it growing robust and healthy (lets face it, other types of macro algae pose too many problems to be used for nutrient reduction, some grow too slow, some are too prolific and invasive).
Ultimately everyone should tend to gravitate toward whichever they "like" better from a maintenance and aesthetic standpoint. I ran some pretty unsuccessful refugiums for years and wouldn't likely run one again unless I had a dedicated fish room and could use a large tote of 50% of the display volume or large to run a large amount of chaeto with circulation pumps, easy access to manually turn it, and high quality high powered lighting. I'm not in that situation. I've been happy with the ability of a large turf scrubber at drawing out tremendous amounts of nitrate and phosphate, so I'm rolling with that. I supplement pods manually
