I'll put the value of a proper press release submitted to a journalist and resulting in an article on a pr8 newspaper website up against any and all of the craptackular free press release go no where sites any day of the week and ten times on sunday.
1. for the seo benefit, and
2. for the traffic
Read
this v7n thread for a start and email me if you want a heads up when the how to book is ready for download (details in the thread).