Welcome back. That is a great size tank to start with.
Advantages to live rock is quicker cycle, less ugly phase and really can get to adding stuff to tank faster.
Also intersting to see what comes on it.
Disadvantage. Pests. But can be a big one.
I always go with mostly regular rock and add about 20% of my rock live rock. My lfs has it and i inspect it pretty good before i snatch it and tote it home in buckets of saltwater. I got loads of pods. Great sponges for sump for filtering. Feather dusters. Of course corraline and bacteria to get things rolling.
I also got bubble algae and vermitid snails. Which both suck. Got lucky and no aptasia.
For me i always start with some live rock. Dry rock will lead to alot of frustration because most people dont have the patience to add stuff so slow as dry rock requires. I know i dont