Not really very useful
933321
Very flimsy, doesn't hold nearly as much as it indicates, and every time you take a can out, the thing falls apart.  Ended up not even using after about 5 months, and then selling it off at a garage sale.
2950073
This was a bit dated and disappointing. It wasn't as useful as I thought it would be.
3744989
I can't say that this product really impressed me. Yes, it was very inexpensive, but the build quality is on such a low level that is makes many of the tools less valuable.

For example, the knife is quite dull. It cannot make super smooth cuts, which is the primary usage most of these kinds of wallet tools see. The ruler isn't very useful at all (mine isn't even labeled). The saw itself is dull and has no real practical purpose. The wrenches and bottle opener works OK, but they are both still a bit of a pain. Finally, the case it came with does not really protect the other items in your wallet or bag from getting beaten up by this thing.

While the price on these are super low, this is one of those things where you get what you pay for. Looking back now I would have preferred to spend a little more on a slightly higher-end wallet tool given the functionality of this tool just has not impressed me.
4421602
I did not find this book particularly helpful. It has a lot of pictures and some useful information, much of which seems arbitrarily placed under a given month, when it could have been placed under any month. This is a nice coffee table album, but not a very practical book. I was hoping that it would include information that a new home owner would need (for example, when to open or close crawl space vents, that kind of thing). The book has a little bit of thins, but it is not well organized, and it is not complete. It leaves an impression similar to that of a pretty magazine.
4500315
It's not all that well thought out. It's overly simple and doesn't offer much information at all.
545761
Not really useful. The pillow is too small to bring the screen up high enough to be useful.
917203
I did not find anything really useful in this book.  I still have it, hoping that some of my problems will be listed (or solved) within.
900797
Most of the vehicles I have to use this on will give me nothing more than codes stored... Very limited and only marginally useful in many cases. Seems like a really cool tool if all you need to do is read codes and clear them. Other than that Just an OK gadget.
3181748
This is a summary of much that is easily alternatively available for free with an easy web search.  It isn't a bad book, it just isn't that useful/helpful.
2673176
Not particularly useful.  Just rehashed content from all the other books of this type.  No real insight.
457213
I didn't think that it helped that much. I could do reviews and find out all of what the book said. A waste of money, basically. Found more info on the web than in this book.
1651926
meh. Not particularly useful for backpackers, since too many of the suggestions are weighty.
Perhaps it's useful for a first-time car camper...
4767473
I purchased this item to use it on my Sony Alpha camera for doing macro photography of insects and plants. It is not very useful in my opinion for either of those endeavors. While it does magnify the subject, I think that it magnifies them too much. As many others have said, you lose the view of your cameras display settings within the viewfinder and  you are limited in what you see magnified. It just is not practical to have to first set your shot up with your cameras viewfinder and then use this one for fine adjustments. I say just get a 1.3 or 1.5 viewfinder that you can permanently attach to your camera and be done with it. This has found a spot in the bottom of my camera junk draw.
3340099
I did not find this book to be especially useful. I bought this book as preparation for a faculty position in engineering that I am starting next year. While the book did offer some interesting insights, I didn't get much in the way of specifics. For example, the book reminded me that freshman may have poor study skills, may be adjusting from being away from home for the first time, and come from a variety of backgrounds, but it offered no concrete information on how to accomidate those problems in my lectures, teaching or syllabus.

This book tries to cover teaching and research together. I would recommend getting separate books on these topics. I haven't yet found a good book on teaching (although McKeachie gets a lot of citations), but At The Helm: A Laboratory Navigator is an excellent book for starting a research lab.
2433951
I've had other Haynes manuals, and this one is more general than most. Its not very useful at all. I wouldn not recommend it.
4592048
Might be helpful if you are really technically challenged.  Also useful to get an idea of what a ROKU does.  Basically re-copies the instructions.  Nothing very insightful.
1353914
It really wasn't that useful to me - was more or less basic information I already knew.  Good for a beginner though.