I use ND filters all the time with colour film. Bright sunshine here in Oz, and with slow shutter speeds and a liking for wide-ish apertures I more-or-less have to. I've only ever used Schneider (B+W) ND filters, which aren't cheap (and are possibly OTT) but to my eye they really are neutral as regards colour shifts. (Mostly 2-stop filters, one 3-stop and one 8-stop 😱 which was somewhat accidental but which has proved occasionally useful.)
...Mike