Omega Pirate Vs. Thardus

Omega pirate, hands down.

I'm on my second time going through the game right now and Thardus was a paper tiger. He beat me the first time because I got cocky. The second time, I kick the crap out of him.

Impulse: I want a lawyer!
Lex: And I want a Ponytail, disappointment abounds!

Omega Pirate was much more difficult than Thardus, in my book.

Metroid Prime bosses ranked from hardest to easiest:

1. Meta-Ridley
2. Flaaghra
3. Omega Pirate
4. Metroid Prime
5. Thardus
6. Parasite Queen