Imo it is not possible for google to detect properly spun content, it is not worth computing power it requires. They can do this using ngrams for example, but it is uses a lot of queries. And for example article spinner I coded beats this algo, so google cant detect that the content is spun. Manual spinning is also good but it takes more than 30 minutes per article.
X-Spinner has super-advanced functions such as auto-grammar fix, for example it will correct "a apple" to "an apple," plus it can spin "I want to eat the apple, orange and banana" to "I want to eat the banana, orange and apple." We can't list all functions here, there are too many to list! - But one thing is sure, X-Spinner will give you the best rewritten article - no other spinner can do what X-Spinner does!