It had everything, Shran, Romulans, Stealth Ship, Tellerites, good storyline, intrigue, action and Molly Brink. Excellent.
Indeed. The Romulan/Aenar arc was excellent. I'd say it tied with the Vulcan arc and the mirror universe arc.
Babel was an excellent episode the Andorians and the Romulans and certainly made for an interesting story arc.
I think this 3-parter is a perfect microcosm of what "Enterprise" SHOULD'VE been all along: You have these races who've never really gotten along coming together for the first time. We know that this alliance will plant the seed of a truly great institution and we get to see it happen.
Its really a great pity that Enterprise wasnt allowed to build on this story arc, and show some Romulan War episodes in a possible Fifth Season, a great pity indeed.