Captain Underpants is better. the standard storytelling instead of the single character-diary premise fitted better for it's story. the status quo was always changing and it had character arcs, worldbuilding, and felt like a real world. plus it actually had an ending, but the last book with the fart gym teacher guy i didn't read then, but i heard it made george and harold gay with each other in the future so unfortunately thats pozzed. i also read the first 6 dogman books but i don't feel like reading children's books anymore.
Diary of a Wimpy Kid while the first several books have been pretty good the books have taken a dip in quality and since the 10th book it lost the plot. since the 9th book every 2 books has been about some wacky vacation or road trip and the stories started becoming random nonsense. it's clear the author has ran out of ideas and the series is being milked completely dry forever for the liar money. the LLBs people make can be good if you look for the right ones.