My shower invites are going out soon, so I'm trying to round out my registry. I'm looking for recommendations for crib mattresses! We'd love to go organic, but I'm uncomfortable putting it on the registry since the price is nearly three times a standard mattress. I figure the next best thing is a good, quality mattress from a reputable company and an organic mattress cover. What are the pros and cons of foam vs. innerspring? I'm so lost!