1. It is based in part on the excellent monolingual "Diccionario de uso del español" by María Moliner, which is highly authoritative and impeccably accurate in terms of actual language usage, as its title implies.After trying various "free" dictionaries, I paid the money for this: and was delighted! Worth every penny: a really professional tool with loads of real-life examples (which are very important: English speakers will often imagine they understand the word from the cognate English, but meaning and usage in Spanish are often significantly different).
2. I much prefer the WordWeb dictionary interface for which currently only the Chambers dictionaries appear to be available.Best feature: Definitions are followed by examples of the word as used in sentences and phrases, including special expressions or idioms.
3. As a Spanish professor, Collins has long been my choice as a bilingual Spanish-English dictionary.
4. There's no setting for defaulting to Spanish or English search.
5. Each time I look up a word I learn much more than just an English equivalent.
6. The examples give a sense of the living language.This app (the premium version) is pretty darn good.
7. Grouses? I can't find the all-important conjugations, which annoyingly seem to be available in the Apple version.
8. Search functionality is very limited; there’s no full text, example or idiom search.
9. isn't included (many dictionary apps do include this).
10. Word of the day behavior has improved slightly, but it is still confusing and not customizable.
11. Not as complete as the unabridged hard-copy version, of course, but still very usable as a quick resource.