Google is getting VERY good at catching spun content so you'd better be talented at manual spins. If they DO catch you, of course they'll spank you... and hard. So anything you use spun content on is inherently AT RISK. Worse yet... Google gets better at finding spun/poor content every year. So in the longrun you're screwed. I'd weight your other options and see if you couldn't find a cheaper source for manually hand written content.
Rewriting your article by hand is the classic approach that is slowly dissolving, however, many people still prefer so. Write manually and then rephrasing to ensure the finest quality is the safest way but it can often hours, days or weeks to finish a writing task that can otherwise take only a little time. And that’s why there also exist people who like to save the trouble and their time, so they look for an article rewriter or article spinner to do the job.
It's a long, long job to research your keywords, keyword phrases, LSi's etc and then to write content for your chosen search term that has the perfect keywords, and the perfect density of those keywords. This plugin looks at the top 10 Google SERPS for your search term, compares them to each other, and then tells you the keywords that ALL the top 10 pages are using in their content, PLUS the density of those keywords. In less than a minute you will know EXACTLY which keywords and their relevant density to include in your website copy so that it matches Google's exact keyword expectations. Click here for more details.