Once I found out that the average price for a decent baby mattress was around $100, I decided that I'd better do some research before buying. I first jotted down a few things I was looking for in a mattress: 1. Firm; 2. Water repelent/resistent if not waterproof; 3. Anti-bacterial; 4. Anti-static. Amidst my search for such criteria, the Sealy® Baby Posturepedic® Crown Jewel® Crib Mattress (by Kolcraft) was the one that impressed me.
It is constructed with heavy guage steel border rods which help maximize firmness and durability. It met my minimum 200 spring coils with 220 POSTURETECH® coils (I've seen more in other mattresses, and while quantity usually equates to a firmer mattress, it also depends greatly on the quality of the spring coils used). It contains 3 Anti-bacterial layers and is reinforced with STAPH-GARD® which inhibits bacterial growth and provides an anti-static surface. Finally, the cover is a dream to clean! It's vinyl-like surface wipes clean with a damp cloth! It also claims to resist stains, odors, and mildew. I clean mine everytime I change the bedsheet (about once per week). Despite one accident which circumvented a diaper, I still have yet to find a stain, smell any pungent odors, and see any signs of mold or mildew... knock on wood...
While this mattress was a bit pricey, there are others which are even more expensive. This is definitely worth the investment since it claims to double up as a toddler mattress.