I have to give paleo credit for getting people to give up donuts, cookies, white bread and dairy. If their version of paleo also means lots of fruit and veggies, I think their health does improve and they feel better.
As far as evidence goes, it seems that beans are in the running for the healthiest food group in a large number of the most credible studies. I never understood why Paleo bans them with its vague reference to phytic acid. There is a lot of evidence that just substituting beans for meat whenever you can takes health and longevity to the next level.