3Birds has a really solid product.
The first question was deliverability - 3Birds has a great knowledge about email deliverability and some solid processes in place. Many dealers have ruined their ability (or are ruining it) with far too many mass emails and by sending them through the wrong channels. 3Birds can certainly help in this area.
In regard to the SEO - yes, it is a site based off the newsletter - but it's a bit more. All enewsletters have sites that are where the customer ends up - but 3Birds has a site that is for enewsletter itself and on that is rendered differently through CSS to be optimized properly and show appropriately in a browser. It seems overly technical, but its a major benefit.
The tool and the included content are pretty powerful too - I'd definatly check the product out.