I have used it and it is worthwhile to use for one 3 month period... I would not use it ongoing... In regards to seo it has many tools similiar to IBP which is the best seo software out there... It is worth it if you have the ability to utilize all the tools... It will help you change your keywords etc.... It will give you extensive reports etc...
For the money I think it is worth a one time shot... Spending the money on seo or anything else??? Seriously, I don't remember what it cost but I think it was around $30 and you are not going to get any seo for that... IBP is very, very expensive and for $30 you are basically getting to use a few features...
I would also recomend downloading the demo or triel version of internet business promoter and ariales... I spent the money on these a while ago and it was a ton of money actually but it has been the best thing for me. Time saver like you would not believe....
If you want more info on the godaddy thing let me know. I have it on one of my sites right now. I don't have the need for it really but I can give you info if you need it...