This episode is artistically impressive and well-acted, and the plot-arc decision is clever, but it lacks the oomph of Threshold.
The full details can be found at the Stargate Wiki - this story sounds better on paper than what actually comes out on your DVD set.
There were several really good decisions made in the course of scripting this episode:
However, I think they whiffed a bit on the chance to see Teal'c really reflect on his life with the SGC. This could have been an updated version of Threshold, where Teal'c is once again near death do to symbiote withdrawal and relives the good and bad times he's shared with his SG-1 counterparts. Making him a firefighter in a world with which we are unfamiliar is creative, but it ultimately feels unrewarding. I don't think we really learned anything about Teal'c from this dream. Not to mention - although Teal'c has studied Earth and its culture - especially American culture - I don't think he can really relate to the life of a full time city firefighter, so the exact choice of dreams makes little sense.
In my opinion, this story should have been about Teal'c questioning whether all of his efforts to fight the Goa'uld had had any effect. He's on a battlefield with a thousand dead Jaffa around him and we don't really get much introspection from him about the meaning of his resistance and the need to keep on fighting? When he is rescued and put on Tretonin, it should feel, to the audience, like Teal'c has come to terms with his efforts - like he has rededicated himself to fighting for his people despite the many setbacks his campaign has faced. Wouldn't that have been nicely symmetric? Oma helped Daniel to realize that he couldn't control the vast evil in the galaxy - that he could only make himself a good person and do whatever was ion his power to make a difference. Wouldn't it have been cool if he'd played the same role for Teal'c?
All in all, this isn't a BAD episode, but it just doesn't really hit the mark emotionally or thematically for me despite its many good choices and artistic presentation.
The script, despite thematic flaws, is clever and the presentation is giving it a boost, since it's so well done and eye-catching.
Chris Judge does a pretty solid job conveying his confusion and frustration with the illusory world, but I think Michael Shanks was a bit flat, to be honest.
This is where the episode suffers...it doesn't send any coherent messages when the plot concept was an opportunity to send a big one.