I do prefer the ST-R version with the upgraded Constellation wreckage (having an asteroid bounce and split against it's hull during an establishing shot), the dynamic ship battle with the DDM and the reworked Shuttle stealing scene where Decker lifts off before waiting for the turntable to finish rotating him to flight position, which remanded me of a dramatic helicopter escape.
My only disappointment is the design of the actual weapon itself. It does not even look like a machine, alien or otherwise. It does have a nice overall shape and texture, but it looks like somebody was in a hurry and had to make it during a lunch hour...
Visually speaking, the amount of damage to the Constellation--both the original and reimagined versions--has always bothered me.
Regarding the original model, there are areas of the saucer that obviously aren't habitable, at least not without space suits. Yet Spock reports to Kirk that only the bridge is uninhabitable--a line necessitated to explain Decker being in Auxiliary Control instead of being on his bridge (obviously to avoid the need to redress the bridge set, costing valuable production time). Clearly, the SFX team preparing the model didn't read the script, otherwise they would have damaged the bridge section of the model, and maybe downplayed some of the other damage.
As for the reimagined version, I always felt the damage was overplayed--the SFX team were like kids in the candy store, not knowing when to stop. The damage to the saucer was most troublesome to me , but I suppose its validity depends on when one thinks Decker decided to beam down his crew.
If he beamed them down before that damage was done, that maybe makes sense--Decker used the Constellation to try to protect the crew on the planet, and the ship took a great pounding. But if he beamed them down afterwards, wouldn't there be some dead crew members still on the ship?
And though many disagree, I think the original planet killer is more visually striking and believable than the reimagined version, which looks especially cartoonish on the interior.