Deimos.fr is now using PageSpeed :-)…feedbacks
What I can say is, it’s very important to take the time to test every optimizations you want to add. I experienced for example issues on silly things like :
# Optimize browser rendering pagespeed EnableFilters lazyload_images;
Some images weren’t shown if you didn’t refresh once again your page browser. I only had this problem on the blog and not the wiki. That’s why you absolutely need to test everything !
This is not a big feedback but what I can say is, PageSpeed is really good, may be not enough mature to avoid tests but does the job quite well.