I have eaten both seeds that I collected in CA and some imported from Chile. Both are equally tasty, being very similar to coconut but slightly more nutty and drier. I actually got some at Vons that had been already peeled but remained whole somehow. They are time consuming to crack yourself. I tried planting some seeds I collected but they never germinated. Nutrition facts on the seeds: 11 kCal each, 82% of the energy from fat (90% saturated). Not the most healthy food, but they sure are tasty!
Jubaea seeds in general are very slow germinators. I collected about 200 a few years ago and just this year got 3 of those to germinate (I tossed out a bunch figuring they were all bad, and now I am not so sure).