I wanted to add something about the significance of this episode in terms of the Vulcan/Human relationship.
I was thinking that one of ENT's flaws is the framing of these little pieces of Trek history. Take our current topic, for example. Human and Vulcan finally decide to take a step towards each other and lay the foundation or a future partnership. As I've already mentioned, the last scene where V'Lar talks about a bond of trust and friendship between Archer and T'Pol is of monumental importance to me in the greater design of Star Trek. But the framing of this character dynamic with a diplomatic mission of very little consequence involving an alien race we've never heard of before or after was probably uninspired. Maybe if it had been something that had to do with Humans, or with another of the great Trek races, maybe if V'Lar's mission had been more significant in the greater scheme of things, the importance of the character development taking place in this episode would have been more visible.
The same happened with the warp 5 thing, or the "Reed" alert - things that make up the core of Star Trek were treated as secondary elements at best.