Mattress Forum

We currently use a "Sealy Posturepedic Mira Loma Queen Mattress", puchased from costco over 10 years ago. We are expecting a little one in a few weeks, and are shopping for a king sized mattress. We tend to prefer firm/ultra-firm mattresses. Tried a few coil & memory foam mattresses. To give you a sense of what we've like....here are some models that we have liked so far.

1. Simmons BeautyRest Elderberry viscoplush (at a mattress outlet)
2. Sealy icomfort Revolution (at Sears)
3. Memoryworks Olivewood Euro Pillow Top Cushion Firm (at a mattress outlet)

We tried a few plush mattresses, and didn't like it as much (eg: Costco's Roseville Plush). We looked into Costco.com selection of memory foam mattress, but are uncomfortable buying it without being able to try it out.
A few questions....

1. We are tending towards memory foam mattresses -- any gotchas to be aware of, especially with a kid on the way? Is it better to stick to coil mattresses?
2. We are looking at buying the Memoryworks Olivewood (from an outlet). Any thoughts on this make/model?
3. The one concern is that purchases from an outlet isn't covered by warranty. How important is warranty when it comes to memory foam mattresses?

PS: We are in the Seattle area.