Reference apps don't get much simpler than Thesaurus. The app, which requires iOS 7 and is US$0.99 in the App Store, does exactly what it says it does: provide you with synonyms - and nothing else.
This minimalist approach definitely has its drawbacks. However, there are still things to like about it. The color scheme is refreshing and bright. As someone who stares at a white screen writing copy for most of my day, I appreciated the pops of color and clean interface.
When you search for a synonym, you get a variety of options, some of which are really outside of the box. Unfortunately, there are not always a lot of words from which to choose. It certainly does not offer the broad scope of alternate word choices available in Dictionary.com's Dictionary and Thesaurus combo app.
You can click on one of the synonyms to open up more words. But just as above, your choices are extremely limited and sometimes non-existent. For instance, if you click on "gaud," you get the exact same synonyms you get for "novelty." This isn't like Visual Thesaurus, which really digs deep into the English language to find the exact word that you need.
The lack of synonyms won't affect most users, but the lack of definitions might be a major hindrance. People often look for synonyms to help them further understand the meaning of a word. If you don't know the exact definition of a synonym, Thesaurus won't help you in that regard. It ditches definitions in favor of its simplistic approach.
If the app is going to throw out words like "gewgaw," it really should tell you what they mean. (In case you are wondering, gewgaw means "a showy thing.")
Plus, not all synonyms can be used in the same context. You can say "mustaches are a novelty right now," but you wouldn't say "mustaches are a bauble." You need definitions for clarity.
Thesaurus also lacks an in-depth look at the word itself. Similar apps have information on the origin of the word. This may seem extraneous to some, but if you are suffering from writer's block, things like this help to spur your creativity.
As a writer, I need layers of options. This app looks nice, especially compared to Dictionary.com's cluttered appearance, but it is not robust enough for a serious wordsmith.
Of course, not everyone is a writer. Most people do not need or want a complicated reference app with a lot of features. If that's the case for you, then you'll probably love Thesaurus.