They're not. The Meyer-Bennett-Shatner-Nimoy films were hokey hamfisted storytelling with lousy production values (they all were identified in Hollywood as "low budget genre films) and horribly forced humor and relationships. First Contact blows them away in any of these categories. Insurrection is also better. Generations suffers from MBSN hangover, while Nemesis, while still having superior production values, is a result of the same actor ego problem (Spiner and, to a lesser extent, Stewart) that gave us the atrocity of STV TFF. Given a choice right now to watch any Trek film, I would pick JJ Trek, followed by TMP and FC.
yes, you can go right to TMP, with its superior production values, slow and tedious storytelling, thin plot borrowed from a TOS episode, stiff and awkward characters, and padded with a half-hour of special effects.
And ridiculous-looking uniforms.