Definately.... there are people around claiming to bring ur website on top but they fail to do so and even i was a victim of such... rather than that i manage to get my self to learnign SEO and i got the results far from what other commit... though im not first on google for my 2 keywords but as i work though i manage to be on the first page of google search after 2 weeks of launching my blog... currently working on the thir keyword...

regards 

yes they are helpful but they have their won limits .... though much of the task cannot be performed but u get an overview of what needs to be done and what not .... i have used several but i prefer to use manual methods rather than using the automation process and jumbling all things together