PRWeb is a great way to distribute PR news.
We had a product that we used PRWeb to send out to newspapers and online sites. I was expecting more but the results was just as surprising.
If you are looking for huge traffic after the release, chances are you would be disappointed. Hits do come in from PRWeb but these tend to be qualified leads.
It does help SEO, but not as much as you wish. But that aside you may get a lot of other leads that PRWeb generates.
For example, we had an offer to be on TV, so that does help long term.
Either way, I think it is worth the $349 we paid PRWeb for Premium. I am not sure about the advanced package, but I am sure it will be interesting if someone shares their story also.