I've heard of the Five Love Languages but had never read any of these books and was not super familiar with them. Lately I've seen this mentioned more and more by people I interact with and/or fandoms analyzing relationships through this lens. And it just so happens my library had this version (the one for singles) so I decided to pick it up on a whim.
From what I understand the book is not all that different from his original version so if you've read other versions of this book I imagine you might not find it very useful or new. As for me I could really only skim it. I'm not into self-help books and didn't think the writing was very good. The Christian themes were a bit too much for me (it's just not something I care for) and I'd also agree that it does seem to have a negative view regarding single people.
That said, if you're looking just to learn about the whole deal then this wasn't bad. I could somewhat understand them based on what other people have talked about, plus the categorizations of each (what it says on the tin is a pretty good hint for all of them). As an introduction to them I found I could grasp the concepts of the languages and that they were explained so I could understand them.
That said, that's really all I wanted or got from the book. I wasn't particularly interested in the personal anecdotes or examples. I wasn't interested in analyzing my relationships or looking to find ways to apply the concepts to non-romantic relationships either. All in all I'd say it's interesting and I learned something new but I wouldn't consider the material life-changing or even particularly helpful. I suppose another route one could take would be to take the online quiz and work your way backwards (ie look at the languages that most apply to you) if you want to just get down to the specifics and not read all the other fluff.
The most I'd get out of it is perhaps another tool in helping me analyze my relationships with particular people on occasion but I'd probably use this to better understand why and how people apply this to relationships in pop culture and fandoms. That said, it was a good read to borrow from the library, but I'd take heed of the people who said that it's not all that different from his original and not waste time and/or money if you're already familiar with it.