I started the series after the 3rd book was released, then read the rest as they came out. So I dedicated like 7 years of my teen life to this series. The lore was interesting, a lot of nice mysteries and twists and high stakes action. All of it built up to a major climactic final conflict in the penultimate book and all seems lost, and then the last book was just.... bleh.

I honestly don't remember much about it anymore. I've blocked out most of it since I read it. But I remember how disappointing it was and the complaints I had about it. I wont spoil any details here though, not for the least of which because I'm not sure how much I can remember accurately. But it became clear after finishing the series that DJ MacHale did not have an end goal/outline in mind when he started the series. He was written into a corner and a lot of the final resolution of the whole story felt like a cop out. It also became clear during the series as a whole that he was just winging it sometimes. He didn't exactly contradict himself that I recall, but he definitely hinted at bigger things that didn't pan out to being all that big or interesting on multiple occasions.

The earliest example I recall of these big hints that falls flat is set up in the very early in the first book. Bobby's Uncle, Press, leaves his motorcycle outside of the subway station and tells Bobby not to worry about it because "The Acolytes will take care of it". He didn't elaborate further, and this was clearly hinting at some sort of system of followers or assistants to the Traveller's that operated behind the scenes, serving their needs. But then it later turns out in book 4 that there is not a system of people, there's just one guy. It is just Press's friend, Tom, that serves the same role for Press as Bobby's friends, Mark and Courtney, do for him. Tom just receives the journals Press writes and leaves supplies for Press and other Travellers and picks up their stuff when they travel to and from Second Earth, just like Mark and Courtney end up doing. The reveal of Tom just makes that earlier mystery of who "The Acolytes" are seem pointless, and doesn't really make sense with Press's phrasing. There are more than one acolyte, but apart from the special case of Courtney and Mark sharing the role, there's only ever one active acolyte on any territory. It's just a little irritating to be made to wonder about something and expect a significant reveal at some point only for it to turn out not to be that big a deal. You feel silly for getting excited and anticipating it.

Also, I don't want to say much more about it because it gets into bigger spoiler territory, but the existence of Tom as an Acolyte is, in itself, a bit of a plothole. I wont say more here.