Chiming in to say that the Juniors line is a great stopgap between DUPLO and the regular LEGO themes. Nice simple builds, but also using mostly regular LEGO pieces and no stickers.
Chiaroscuro is spot on with this point. Some kids are incredibly dexterous by 4 years old, and some still struggle at 8. Both my girls (10 and 6) have had issues with some of the finer motions in the past (positioning a 1x1 plate, aligning Technic pins etc) and it absolutely kills their interest in a set when it happens. Making sure that a set is a good fit for their skills is really important.
In terms of the Creator Expert sets, I'd steer the kids clear of them if I were you. Both of my children have tried to help with various modulars over the years and were invariably frustrated. Supa Necta, you've got a prodigy on your hands - nurture that ;)
On another note, if a kid asks to help you with the stickers on your set......
More like training wheels sets before going to the regular SYSTEM style sets. I really wish they would put more Juniors sets out for that reason alone.