This is the PageSpeed section from my .htaccess:
<IfModule pagespeed_module>
ModPagespeed on
ModPagespeedEnableFilters extend_cache
ModPagespeedEnableFilters collapse_whitespace
ModPagespeedEnableFilters combine_css
ModPagespeedEnableFilters move_css_to_head
ModPagespeedEnableFilters remove_comments
ModPagespeedEnableFilters inline_css
ModPagespeedEnableFilters rewrite_javascript
ModPagespeedEnableFilters insert_img_dimensions
ModPagespeedEnableFilters rewrite_images
ModPagespeedEnableFilters rewrite_css
</IfModule>
Whilst there is a little overlap with the js and css compression, I'm not seeing any negative results. I've set Drupal 7 to aggregate and compress CSS and JS.
The site isn't particularly high traffic though.