"Babel One" / "United" / "Aenar":
What a FANTASTIC run of episodes! Definitely the best 'trilogy' story so far in season four. The backdrop of the peace talks, and the coming together of the Tellarites, Andorians and humans all worked very well into a decent plot of Romulan interference.
I thought I'd have my fill of the Romulans, but Enterprise has used them well. I also really liked the development of the Andorian race with the 'Aenar' (have they appeared anywhere else?). Potentially goofy-looking, they actually come across very well.
Again, the sets and special effects for Enterprise look superb.
The only bit that fell a little flat for me is the T'Pol/Trip stuff in 'Aenar' - if this were edited together as a feature length movie you could easily lose most of that stuff and the episode wouldn't really suffer (except for Trip's shock request for reassignment at the end, but you could cut that too).
Shran got over his girlfriend and moved on to the next a little quickly!!
All in all, a great trilogy of episodes, some of the best in season 4 so far!