I think some people are a bit confused between a 'walk-through' and a 'Let's Play'.
If I was looking for proper information, I'd watch a 'walk-through'. Walk-throughs are more about doing it the proper way, so you can gain an achievement or a higher percentage of the game played, or makes you aware of something you've missed,..or whatever. They tend to scrape every corner to give you the information you need. It's more of a 'guide' than anything. However, it can also have comedy; but the player tends to be quieter or not speak at all, so you wont miss dialogue and little tid-bits.
While a 'Let's Play' is usually watching a good-humoured/intereting person/persons play through a game on their terms. They might be thorough and you may be able to garner information from them that may be helpful, but you might get easily annoyed at the fact that they will probably skip a lot of things, and even talk over the characters in-game during a cutscene. It really depends on their play-style. I am usually looking for a good humored/interesting 'Let's Play', instead of a step-by-step guide.
I tend to look for a thorough and more serious 'walk-through' and comedic/interesting 'Let's Play'. Like Tobuscus playing Amnesia : Dark Descent. It's still his best work.