Personally, I upgraded to the Blus, and find them to be very good overall.
Certainly TMP and TWOK are both well encoded (strange color issue with Regula on TWOK the only issue I have).
In my view, the only thing that needs tackling movie wise is to redo the work on the Directors Edition and present that on Blu-Ray.
They look and sound great to me, and the reviews, though not overstating their case in context, do not provide an accurate impression of this aspect of their presentation.
As a Star Trek and movie fan, I am not above picking nits, and while not 100% perfect, they are still very good presentations of the films.
If you have a Blu-ray player, I recommend going that route.