I think I only was happy with the Klingon Bird-of-Prey doing it's Harrier landing.
shareall of the first 4 ST films have great SFX even by todays standards (as does Trek VI), in fact often they look more 'real' as they are physical models. not CGI.
TMP had Doug Trumbal (2001, Close Encounters, Blade Runner) and John Dykstra (Star Wars). then 234 and 6 it was ILM
but Trek V they didnt go with ILM and paid the price!
To each their own and all, but Star Trek IV received a significant increase in budget over its two immediate predecessors and its production values are quite lavish.
It featured groundbreaking matte and modelwork (the bird of prey flying through the skies in all kinds of different weather and sunlight), animatronics (real enough to fool animal welfare groups!) that set the stage for pretty much every non-CGI exotic animal movie that came afterward, one of the earliest instances of morphing effects, TONS of location shooting both outdoor and indoor, much more detailed new sets (compare the bird of prey bridge here to how it looked in part III, and to tjat same movie's Excelsior interior) and more nuanced cinematograpy (I think it's Star Trek's only cinematography Oscar nod).
Whether it looks good or notis in the eye of the beholder- I suppose I can understand if someone thought the alien probe and the warp speed effect on the bird of prey looked goofy, but that's more the design than the effects themselves. Comparing Star Trek IV to its contemporaries (say, Aliens from the same year) I'd say its effectivesness comes off very favorably.