This episode gets a bad rap because it isn't a great finale. But it is an episode on par with most other episodes of enterprise. So, if this were just some other episode, it would probably be about an 8/10. ... And I am solely basing that scale on average IMDb ratings of other episodes, by other people.
As a series finale, it's not great. So if you're looking for a great ending, don't expect one. Maybe just expect a run-of-the-mill enterprise episode, and you won't be so disappointed.