Chris, I don't know what your expectations of "safe" are for your "safe option" question, but if you're concerned with having an easy and painless as possible Hyundai warranty experience, you will want to follow your owner's manual service recommendations and use dealer fluids, parts and service. Will not doing this void your warranty? Certainly not, but it can throw a wrench in the process.
There are many threads on this board in regards to this same topic. I have yet to see where using an aftermarket ATF in a Hyundai product that spec's it's OK for use in SP-3 applications has caused any issues or failures, but many of us choose to do our own research and make our own choices.
In years of following this, I have yet to witness or read of an instance where someone had an under warranty Hyundai AT issue that was denied due to an SP-3 product like Maxlife, etc being used. I haven't seen a single one. Using something out of spec is a different story.
Joel