I liked the episode but it grates on the nerves to have this stretch out so long. First prototype, then the Weapon underwater, then its moved then it launches, then it goes through a vortex, then it stops to be armed, then it goes through another vortex. When will it stop? Oh, the season finale. Character development took a backseat to the various chase scenes. It somehow reminded me of Paris and Kim in one of their black and white holo serials. Simple and cheesy, but fun.
I liked learning a bit more Xindi history and context. I like that that the slow deliberations and prudence of the Aquatics were sometimes all that held the Council together and prevented civil war. Since Degra had the Aquatics build the weapon and it has been shown that the Spheres (and by logical extension the Guardians) were manipulated and destroyed the Aquatics I wouldn’t be surprised if the Aquatics show up at the end and employ their “backdoor” to help Archer-et-al blow up the weapon. The scene with Archer when the Xindi-Primate said that he respected Degra and wanted to see where relations with the humans would go is important. I always felt it was stupid to destroy the Weapon if the Xindi were just going to build another.
I liked Reed breaking up over losing the MAACO and showing Hayes how he cares. However the final part where Reed addresses the MAACOs didn’t ring true because they don’t know how he cares. The Trip and T’Pol interactions were good. I liked her emotion-tinged retort “or you might surprise me with an idea of your own” and the not-overblown “I’m all ears.” Hoshi’s character has progressed from a shy girl to a woman. She stood up to the Reptilians. However, the Reptialians must have low standards if Hoshi just talking back is met with “I didn’t know they were so strong-willed”. She had the biggest development because she tried to commit suicide rather than be used as a pawn, and that’s gutsy.
Technically, I liked the lines of the Aquatics ship, I felt sad about the Anomaly destroying it, and I liked Hayes being beamed out while shot. The whales sounds, from mouths that never moved, is typical. Why couldn’t they put the mouths on top or vibrate them and making clicking noise, or just something unique? Also, everyone they meet is made anthropomorphic in form and culture, except that aquatic creatures can’t have clothes or jewelry. Too predictable. The MAACO shock stick was also too PC. They should have blown his brains out.
Medically, the “parasites in the neocortex” is an annoying bit of pseudo-sci-fi. But fortunately Phlox comes to the rescue with his “osmotic eel.” (Great pick-up line!) When Hayes arrested, Phlox ordered a “.2 joules” shock. I’m not in the medical field, but I believe defibrillator’s are supposed to initially deliver 200 joules and progress to a maximum of 360 joules. (Where’s Tars when you need him :()
The funniest thing was the Aquatics voice synthesizer. I swear that’s the same output produced by the computer in “Collosus: The Forbin Project”. 
Now they are using Degra’s ship to catch the Weapon. I think Reed should have taken more MAACO’s (unless Degra’s ship just doesn’t have the room). And I certainly hope someone has bothered to learn to fly Degra’s ship since no one has ever been aboard one!
NB: Let’s just say Hayes was hit by some of the beam just Before transport and that we saw the rest of the beam shoot through the dematialization space, hmmm?