Even better than EU, you're part of the Nordic Passport Union. Which I believe means you can naturalize as Norwegian with just two years residency there.
If you already have an EU passport, what would be the advantage?
Rules change (see Brexit).
You don't have to apply for a work or residence permit, which means that you can stay in the country indefinitely. If you're from the EEA you have to exit Norway every 3 months, unless you qualify for a work and residence permit, basically, you have to have a job.
Is the 3-month thing actually enforced in Norway on those who do not cause a nuisance or seek benefits? Not only is it rarely enforced in EU countries, but I vaguely recall hearing that there have been court judgements in some country or another that EU/EEA citizens who overstay there cannot be forced to leave.