I'm one who bought the guide just to have item info and stuff like that, which I thought would be helpful but not game spoiling for me personally speaking of course.
An interesting thing happened last night. I found myself unable to get past a certain point in a quest. I must of spent a solid hour or more retracing all steps, looking at every texture in the dungeon to see if and what I may have missed, but all to no avail. Finally I cracked open my Prima Guide, looked up the quest and had a "ah hah, omg am I dumb" moment.
I'm an older gamer, in my 50's. I don't know if that means much or not but I'm rusty at these games and genuinely feel that one "cheat" to get the guidance needed will actually allow me to get past future puzzles and challenges on my own. It was more of a learning experience in how to be resourceful in Skyrim.
Just thought I'd share this, not for the purpose of debate but just for consideration of any that may be on the fence. Aside from philosophy, the guide is actually huge and very well done. I bought the paperback one and it's a great deal for the info. it provides to a game I feel is easily among the best I've ever played, and I've been playing these games since the mid 80;s.
Cheers -T

It's FAR more than just a cheat's guide, it has detailed info on everything the tiny little game manual left out.