I would have given it a 8, but there were things in it that I did not like at all.
One of the things I did not like was the fact Sigma's name was misspelled, which I found inexcusable since it's not that hard of a name to write.
Secondly, why did it show as a young scientist when in the games he's an old man? Were the animators even trying to keep the cartoon in sync with the video game series?
And lastly, why didn't we see Zero? Zero is by far one of the coolest Megaman X characters of the Franchise. Not saying I don't love X, because I do, but I just like Zero a bit more, and the fact he didn't even get to star along side was really disappointing.
Oh well.. while this episode had its faults, it still was one of the better episodes of the series, so it's definitely a 7 out 10 in my book.