The History Channel typically releases programs that have very good production values. Mystery Quest is no exception. The filming is done well, and the editing is reasonably tight, all of which serves to produce programs that are interesting to watch. These programs also tend to fall slightly more on the "pro" side as opposed to the "con" side of the mysterious and controversial. By that I mean, if you watch an episode of Nova, for example, on UFOs, you can be certain the basic tone of the program will be to "pooh, pooh" the subject a little. Mystery Quest leans in the opposite direction. That's not a bad thing, as it preserves the feeling of mystery, which is what keeps us watching and wanting to know more, and curious minds are minds that remain young. At the same time, Mystery Quest balances with just enough contrary views so that the viewer doesn't feel as though they are getting sucked into an overly New Age-ish black hole of silliness.
With the above in mind, be aware that shows like this are put together first and foremost for the purpose of attracting and holding on to viewers, and that means they are edited with great care to produce just that result, sometimes at the expense of what is strictly factual. Friends of mine have worked on episodes of History Channel's Monster Quest, which is the kissing cousin to Mystery Quest. They assure me that all these programs are scripted in the sense that the writers go into each episode with specific ideas in advance as to how they will be presented, and what the desired outcomes should be. The basic framework for each episode is worked out, and then the film segments and narration are pieced together so as to conform to the overall picture they determined up front to build.
This is not to say there is no truth here. On the contrary, many of the facts presented in Mystery Quest are fascinating. Just be aware that editing and narration deliberately try to sway you in certain directions to hold your interest, and to keep you coming back for more. After all, why make a program that is factual, but that kills the imagination along with all desire to see another? That's not good business, and the History Channel IS a business first and foremost. So, keep an open mind when watching Mystery Quest, but not so open that your brain falls out.
If you approach it from that perspective, Mystery Quest is a fantastic addition to your video library. Being somewhat of a WWII buff, and having lived for some years in Germany, I particularly found the episodes on Hitler's possible escape, and the rise of a Fourth Reich to be fascinating. While it is still most likely the case that Hitler died at the end of WWII, as our official history books suggest he did, enough discrepant evidence is presented in Mystery Quest that one has to admit the possibility exists that our history books got it wrong. At least what has been accepted for decades as "proof" of his demise is seriously called into question here. And if the "proof" proves nothing, it leaves the traditional, historical account without hard substantiation, thereby opening up the possibility that things happened in a completely different way. Unfortunately, the program doesn't offer much by way of evidence for any particular alternative. It merely pokes holes in the account of accepted orthodoxy.
All in all, I give this series two thumbs up. So long as you keep in mind that editing of these programs intentionally predisposes you to lean in certain directions so you'll keep coming back for more, there is sufficient factual information provided that it is well worth the time to watch.