Not fantastic, but entertaining
I'll get right down to basics: Artemis Fowl is not the best series ever written. It isn't even close.
What it does wrong are stupid plots in the last half of the series, the weird romantic chemistry between Artemis and Holly, and the rapid aging shaft they gave Butler.
What it does right?
They're fun. They are stupid, semi-intelligent fun that do get younger readers to actually think. They are funny, action-packed, and move along at a faster pace than a tunelling dwarf.
Similar to Mathew Riley, Eoin Colfer writes books that make people that don't read do so, and he does it WELL. That said, if you try to take them seriously, you'll be disappointed.
If you don't, however, it's a pretty good ride - even if Paradox is stupid.