I guess my experience differs from yours. With the Oase whenever I clean the prefilter the filter doesn't need to primed, the floor doesn't need to be wiped and the trapped air goes away by itself. I can understand why you don't like it if it involves so much work, I for sure wouldn't either.As mentioned in another thread, I can clean my entire Eheim Classic in the same time it took me to move the Oase out of the cabinet, clean the prefilter alone, prime the POS, and wipe the floor.
Not to add the following 30 minutes I had to spend wiggling some 10 kilos of filter around INSIDE the cabinet to get rid of trapped air, never getting rid of it all.
Eheim Classic? Open double taps, filter primed and running. Bubbles expelled in 30 secs or less.
I find it a plus not having to handle the biological media during weekly maintenance.
In the end of the day a filter is a filter and they all get the job done pretty much.
Other things to consider when asking yourself if a filter is worth the price tag are longevity, build quality, spare parts availability and after sales/customer support.
Filters can last a long time so sometimes it's worth spending the extra $$$.