Well, since TMP is only available on BluRay in its theatrical form, I have to ask: should I stick to my Director's Edition, or go back to the Theatrical one on BluRay ? I don't remember much about that cut.
I would say the majority will go with the DC, but for me, the theatrical is the superior version. I once read a review where the author suggested the DC was effectively an "out" allowing those who secretly liked the film to actually admit it because this new cut is just "so much better paced" blah blah.
To be honest, I get really tired of the "slow Motion Picture" schtick and such like. It's an immense, epic, Science Fiction opus - I love the extended cloud fly-throughs, I love the reaction shots, I love the magnificent score, I love the pace, I love the FX etc, etc.
The Blu-ray is really decent from a technical perspective also, the best transfer in the TOS movie collection set - and comfortably ahead of all antecedent home video releases. TMP on BD is an awesome experience if you have a quality home theatre system. Turn the lights off, pump up the sound and soak it up!