This book doesn't have much going for it. It doesn't list many of the different "cases" of words (which are very important in Gaelic and are quite irregular). Some people object to it's use of phonetics -- I don't, but I'm not sure they're entirely necessary in a language like Gaelic. Plus, some of the phonetic characters were missing in the copy I bought.
It also has a lot of useful words missing, about half the things I look up aren't there, and I'm in my first year of learning the language.
I bought it for less than half the cover price, and still don't think it was worth it. There are much better dictionaries for only a little more money.