301 Redirect or ServerAlias for Multiple tlds

Our company owns multiple tld's for our corporate domain (e.g. company.com, company.net, etc.). Currently, we operate the main website at "company.com".

To have "company.net" et al forward/redirect to "company.com", should we use a 301 redirect or setup a ServerAlias in Apache's virtual host directive (we use name-based virtual hosting on Ubuntu Server).

Are there any SEO penalties from one approach vs. the other (e.g. Google thinking you have multiple sites with the same contact + flagging it as spam)?

Thanks for the help.

According to google it is better to use 301 Redirect. Excerpt from Google Webmaster Central answer:

People access your site through several different URLs. If, for example, your home page can be reached in multiple ways - for instance, http://example.com/home, http://home.example.com, or http://www.example.com - it's a good idea to pick one of those URLs as your preferred (canonical) destination, and use 301 redirects to send traffic from the other URLs to your preferred URL. You can also use Webmaster Tools to set your preferred domain