I use Nisi filter system but before I bought anything I read a lot of reviews, and bought a lot of the cheaper filters circular ones
and some of the cheaper ones are just as good as the Lee/Nisi, and many more makes,
you read a review and someone recommends a certain filter the next review you read someone critics that filter
believe me the more expensive filters,
you are paying for the name that's all.
Lee have bad colour cast but the say they have no colour cast all
the filter makers claim the same, you can fix in LR/PP
you have to make the decision,
why did I go for Nisi it was just advertised with more spin/ but so far it has served me well yes there is a little colour cast but as far as I'm concerned,
there are NONE that are perfect just my opinion and rant
(I have nothing to do with Nisi )
Tom G Scotland