The material in question is not a foam product but a Thermoplastic polypropylene honeycomb supplied with or without a non-woven polyester veil or scrim. I should have been more clear on that as Nida-Core makes a few different products. It's been around for a while and is used by pro builders. You don't fill the honeycomb if that was your question in reguards to epoxy filler. I may need to post this in the builders section as I'm looking for someone with experiance using it on an amature level. Ric Caselli featured on Richards latest news page has used it on his Mirage's bridge deck and reports all went very well with it. I'm looking at hull building though and would like input on that. We are 75% into the bridge deck and the only place left for it would be in the cabin furinture and the cabin roof.
Another company making this material is Plascore and Hexcell. Plascore is a US company while the others are imported. With the high price of plywood this stuff very competitive price wise where as it used to be completly out of range for me.