Hands down, a NUC is much easier to install with fewer steps and less issues. With a NUC it is simple. Transfer the frames, dump in the extra bees, put the cover on and walk away. With a NUC, at least 5 frames will have drawn out comb, the queen has not only been excepted by the bees, she has also been laying eggs for weeks nonstop. The bees have been storing honey and pollen for raising more brood. The colony has been established and will grow instantly with a laying queen. The chance of the bees superseding the queen is much less.
For installing a package there are more steps, which means more to go wrong. Package bees don’t come with frames. So, there is no drawn out comb and normally a new beekeeper does not have drawn out comb on hand. The queen is caged which means she has NOT been laying for days and will take a few days to start up again. Most new beekeepers don’t feel comfortable of knowing when or how to release the queen.
For these reasons, but mostly because package bees have a higher rate of superseding the queen, we recommend new beekeepers start with NUCs. A NUC will give new beekeepers a better chance to be successful the first year. It’s a fairly large investment getting started with bees. Better to play it safe the first year.