I still believe there are 4 categories here that are very different:
1. Template in a Box
2. Non-Templated Platform Solutions
3. Custom Web Development Agency
4. DIY
Doing it Yourself implies building it in-house, which is very different than hiring a professional company that has done many projects before. I also know, in my vicinity, at least 4 other development studies that have no issues retaining developers and designers. Maybe it's just a Canadian thing
At any rate, all personal/company opinions aside, I recommend everyone chooses something from options 2-4.
Having a site that has the same structure as everyone else, same color scheme, same flash assets, same contact page, etc is not a benefit. I have yet to see a single piece of data showing that there are SEO benefits to templated automotive sites, but there's plenty of data showing the positive impact of Wordpress (with plugins) and other platforms that are not so strictly templated, but have a proven back-end that can deliver results indifferent of the front-end theme.
Make sure when doing your research you ask about:
a. Ongoing improvements to the website
b. SEO experience with the platform (if existing platform is being used)
c. Experience with some sort of retail or product-based development
Just my opinion.