The first half is, somewhat, more successful, for me, simply because I like the sense of anticipation and seeing a narrative build. This is a deep-seated psychological kink of mine that I am unable to shift. Not that I want to, as such. I do also think that TMP's first half may also be the leaner and more focused of its two halves, to one degree or another, but I actually think the difference is rather trivial, in the grander scheme of things.
What the first half offers, amongst other things, is a sense of drive, where the humans (taken to mean actual humans and human-like characters) wrestle with their personal desires and must adjust and balance themselves sufficiently to be permitted passage into V'Ger and the second half of the picture. This is also metaphorically expressed in the balancing of the Enterprise herself. In this sense, the first half is about readying for exploration, while the second half is the process of exploration itself.
When exploration is undertaken, extreme patience and diligence are essential qualities if one is to have any measure of success or cumulative sense of reward. One of the things I admire about TMP is the implicit, albeit uneasy, trust, between V'Ger and the Enterprise (and its crew; this I place in parentheses since V'Ger primarily recognises the Enterprise, not the "carbon units"). There is tentative, even volative, but sustained mutual curiosity between the two. In essence, they are both children. That child-like sense of wonderment is beautifully conveyed in TMP's second half. For instance, certain shots and moments in TMP's latter half are, to me, very humbling, as any journey into the unknown should be.
For as much as, in Roger Ebert's words, a film is not about what it's about, but about how it's about what it's about, TMP is not merely the mechanical telling of a series of events in the fictional lives of fictional characters, nor even about one set of ideas, themes and motifs or another, but a cinematic expression of how humans get things done, what motivates them, why we're motivated at all, and even more fundamentally, as Roger Ebert's maxim implores us consider, the means by which that can be celebrated in art -- in this case, as an elegant work of speculative fiction, with long shots, clipped, precise dialogue, characters maintaining their poise and dignity even in the face of threats and intrusions both personal and impersonal, production design that is at once sleek and refined (Starfleet) and dark and baroque (V'Ger), and a gorgeous, mellifluous score that allows everything to play as an epic ballet, faintly recalling The Blue Danube in "2001" and a million things beside.
If it's not clear, I love TMP. It's a wonderfully evocative motion picture, more than worthy of its name. The title, by the way, as opposed to something like "In Thy Image", and especially a diminutive sobriquet like "The Movie", perfectly riffs on its source material's small screen origins, placing cogent emphasis on the idea, much like the design of the Enterprise and interior earth-tone aesthetic, that Star Trek has been consciously reworked, expanded and evolved into something more stately, grand and wondrous. At least, for one little motion picture, way back in the Christmas of '79.
