Great name if you gonna develop a site for it and do some SEO.
23000 searches on O for that term.
Searchengines don't care for the extension but for the term.
One of my domains is
#1 on the google germany search results pages for a very common TM term - and it's even just an empty masked redirect frame page, so no own content.
But the best part is, i didn't even submit the page; google found itself and ranked it
#1 just because the domainname matches the searchterm a 100% .
So if you do careful SEO chances are even your .ws domain gets a high rank for the term "diet plan".
If you registered the name for resale though, it's worth almost nothing.
Any extension other than .com/.net is only good for development.