You will be ranked well if your keywords are in the correct sequence, and targeted towards a searcher looking for quality relevant content.
Hyphen is seen as a space to search engines. But equally speaking, so is null. AppleMango is seen as 2 words to a search engine because it recognises them as 2 separate words.
You may have advantage when people type "Apple Mango" to search. But if people type "Mango Apple". I wonder how SE handle the keywords in reverse order.
it's not for seo. i think applemango.com or mangoapple.com is taken. domains with - is not easy to remember for visitors
Because domains are frickin' expensive these days. If a person could find the right combo of words without the hyphen, he'd take it; but it's becoming increasingly impossible to do so.
I think hyphens are used in desperation sometimes, always try to get a name without a hyphen, hypens are just annoying for the user to remember and enter into a domain address.