I see that I neglected to report back on my own initial playthrough of this box set.
I ran it for two of my daughters and two of their friends (so two 17 year-olds and two 13 year-olds).
They had no trouble picking a class, species, or background. I had already sorted out the equipment and spell cards. I also gave them each an index card on which they could write their character's name and personal characteristics (age, height, weight, etc). I had my copy of Xanathar's on the table so they could look at the lists of names in the back.
One thing that's a little bit awkward with the card setup is that some species modify things on the character sheet, but since the sheets are pre-printed, it's tricky to note that down, so it becomes a matter of expecting the new player to remember. For instance, the two younger teens picked elf as their species, which gives their characters a +2 bonus to Survival checks, but none of us remembered that until my daughter noticed partway through the session.
My other daughter was playing a dwarf, which gives her extra hit points, but at least she can mark that with extra HP tokens.
Anyway, I started them off as friends looking for adventure on the edges of civilization. On their way to the keep, they encountered Mallyn's wagon and destroyed the gray ooze glob in it. They found her horses and brought them back to the wagon. After arriving at the keep, they unpacked the wagon for the trader Oleira and met Mallyn's uncle. They then went and met with the castellan and his advisors before heading back out into the wider keep to do various tasks.
They spent the night in Cornflower's hayloft then they went exploring the woods, where they came across the sprites looking for sparring partners. The sprites knocked them all out.
I think we stopped for dinner at that point. The younger teens hadn't been all that engaged - they were shy and giggly and kept going on their phones (even though I had asked them not to use their phones at the table). They weren't interested in continuing the game after dinner, but the older two were, so I ran another session just for the two of them.
They explored enough of the wilderness to level up to 2nd after taking another long rest at the keep (this time they got a room at the inn). Then they went to the Caves of Chaos, where they befriended the kobolds, convinced them to take the dragon home, then killed the giant centipedes.
They then went over to the goblin cave, where they proceeded to insult the goblin boss (unintentionally). I had removed some of the goblins to account for there only being two PCs, but the remaining goblins were still able to take down both PCs. I decided that they would capture the PCs and chuck them in the room with the dwarf NPC prisoner.
My older daughter's friend is keen to keep playing D&D, so next time we are able to play again, we'll start with them trying to free themselves from the goblins' bonds (and potentially befriending the dwarf NPC).
I love the spell, magic item, and NPC cards. I wish WotC would produce these for general use. I'm not so sold on the character sheets or the other cards. I think if I were to run this again, even with new players, I would use regular character sheets with fully pregenerated characters like the original LMoP starter set had.
I think I would also happily run the three-booklet campaign just as a starting adventure even for experienced players. It's a solid little sandbox with some great encounters covering all three pillars (RP, exploration, and combat).