If users submit a lot of good quality articles on the site, what is the best way to approach the meta description tag?

I see two options:

• Have a description box and rely on them to fill it sensibly and in a good quality way
• Just exclude the meta description

Method 1 is bad initially, but I'm willing to put time in going through and editing/checking all of them on a permanent basis.

Method 2 is employed by the stack exchange site, and lets the search bots extract the best part of the page in the SERP.

Thoughts? Ideas? I'm thinking a badly formed description tag is more damaging than not having one at all at the end of the day.

I don't expect content to ever become unwieldy and too much to manage.