Their is a saying in the VC world of eating ones own dogfood. Ie, if your product is as good as you say it is, then by all means you should be totally immersed in it personally, and that includes being power users. Far too many web designers, and SEO firms do not eat their own dog food and end up making bad impressions by doing the following.
Spam marketing to the wrong market sector. Dont market real estate based SEO to a manufacturer, or food based SEO to an aviation concern.
Nothing instills a lack of confidence like showing your best efforts on your own broken website. Sure, its a pain to keep up with browsers, and even screen sizes. Otoh if you want to impress potential clients, a page with CSS splattering your content randomly on the screen, no matter how cool the art is, if its not readable is not cool. Its the same with broken website navigation, or errors so bad, that a users browser throws up and is unable to render. Such does not inspire confidence.
Retro can be cool, and 1994 style websites can create authenticity in some markets. However, years old SEO techniques are not. While a cool sales pitch may impress the uninformed, is not going to fly worth a hoot unless there is little to no competition. (albeit, flying not worth a hoot, is better than not flying at all, but its still not cool)
A coder does not a website builder make. Ive built hundreds of sites over the years, and while technically they work and get the job done, I am no graphic artist. I know this, and as such outsource the presentation arena to people who are for other than my own sites. Sadly, far too many recently unemployed coders think they can do websites, and just as with my work, the underlying code is solid, but they dont spend the money for a graphics person. It shows, and it is not impressive.
SEO is only part of the game, and realistically, its a tiny part. Traffic without conversion is just burning up server dollars. It doesnt pay, and often times ends up being a negative ROI. Just as one would not go to the expense of prime billboard space or tv ads unless they had the ability to fullfill orders, it makes no sense to spend money on SEO without the rest of the game plan in place. Certainly there are situations where traffic can be more important than conversion, but they are a rarity, and often times more of a specialized internal thing, than an external deal subject to outsourcing.