I think the big problem with Lee (and maybe other brands), if the reports are to be believed, is inconsistency between batches. Some folk swear by them and others swear at them.Some seem to have very little colour cast, some a blue tinge and some a magenta tinge. Given that it is so easy to produce a Lightroom preset to correct whichever (if any) colour cast a particular filter produces, it probably does not matter too much. Apart from snob value, the £5 cheapos from China via eBay are probably as good as anything more expensive. Certainly for landscape work.