I am wanting to get one as a gift for a friend that is helping me build a small bookshelf. The $40 is much closer to the price range I'd like to spend, but I don't want to get him something he won't use. Should I get him the $40 set or just a gift card to the local hardware store?
When I'm spending money I like to read the negative reviews on a product online. This tells me what is wrong with them and I can decide if the issues are something I can deal with or if it happens to be an 'unlikely' occurrence.
Now with a dado set, the first question would be how much would they likely be using them, and what quality of tools do they normally buy? I have a $240 set sitting on my wishlist at Amazon, because it rated very high and was a high quality set. It's been on there for 4-6 years. So while that is the set I would really like, as long as the set isn't crap, I would likely be happy with a much cheaper set. The big thing is will I have to replace it after some medium use? I also generally avoid (after experience) buying the cheapest of any tool, as I usually end up buying another one not too much later.
So the point is: know your person. Some care very much about what tools they get; others, not so much. If he doesn't have a set, then he might really appreciate them, but he might also be saving up for a nice set and if that was the case getting him a gift card to help might be the best solution. Ultimately, asking him which he would prefer might be the safest option.