Hi mjosta,
I don’t have enough complete information to make meaningful comments for you on the mattress you’re mentioning. The latex would either be a 100% NR or a 70/30 SBR/NR blend. Either type would be a good quality material. I’m not sure what you mean by a “thin CertiPUR layer”. I’m guessing you’re referring to the quilt panel that has a layer of polyfoam in it. How thick is the piece of foam(s) in the layer. What is the density of those foams? CertiPUR-US refers to the certification of the foam, but doesn’t tell anything about the density/quality. I’m guessing the foam is 1.5 lb. in density based upon previous conversations I’ve had with Verlo, but I’d want to know for sure.
What is the design of each spring unit? Is it an LFK? Marshall coil? Continuous coil? Spring counts are more of a by-product of the overall design of the spring, so that’s not a reliable indicator of innerspring quality/durability. In general, the spring unit will not be the weak link within a mattress.
I strongly recommend some type of mattress protector to keep a healthy sleep environment for your child. If you’re looking for a list of a few more mattress protectors, including some more “natural” options, then you can go to this mattress protectors post #89 here. Most of the stain protection guarantees on protectors like this apply when you buy the mattress and the protector together. If the protector fails, the protector is replaced and then you’re usually instructed in methods to try and clean the mattress (or a cleaning kit may even be sent out to you). If that fails, the protector company will often replace your mattress, because stains do void your warranty. You have to read these warranties completely, as many of them require you to contact them within a very short time of the stain happening.
If you can reply with a few more specifics about the mattress you’re considering, I can then provide a bit more complete feedback.
Phoenix