I saw Pearl Jam at the Camden amphitheater in 2006. It wasn't a great experience. Camden is a hellhole. I had Ten Club seats in the back of the 200's and couldn't see anything. The sound was OK but nothing spectacular.
I've only been to outdoor venues on the East Coast, but Camden definitely doesn't belong on a top 5 list.
Merriweather isn't perfect, but I've always enjoyed being there.