Are activity gyms or plain foam mats better for newborns?

It depends on your goal. Across the communities we read, activity gyms (Fisher-Price, Baby Einstein, Lovevery) get credit for entertainment and developmental stimulation that buys parents hands-free minutes, while plain foam mats and interlocking tiles win on cushioning, easy cleaning, and longevity into the crawling and walking stages. Many parents end up owning both.