The main problem I had with this story is that it could've been so much better, especially the ending - It was incredibly cheap... instead of SG-1 solving it themselves they basically got lifted up by a magic fairy and cured.
It just seemed like a quick and easy fix, one minute they're on the planet and now their home back to normal... what? Oh well there is some good points to this episode as well - I did enjoy the Vala subplot and seeing her crazy antics make me laugh so I'll be a little forgiving of this episode.
I would've rated this a 5 but i'll give it a 7 because of Vala's subplot. I do rather enjoy brain eating paracites but I do not enjoy illogical quick fixes at the end of episodes.