Academy X has an edge because they had a series and have had a lot more development (not recently though). I chose Academy X because they have a bit more narrative heft being the "last generation" of mutants for so long. These kids really did the heavy lifting of making the Decimation years meaningful. The weight is a blessing and a curse since so many of them were made disposable devices in order to raise the stakes. Messiah Complex was the first event I collected in floppies, so I'm a bit biased since Academy X tied into that event (I didn't read the entirety of the run until much much later). This is also the generation that moved to Utopia and put in the hard labour of building it. They really don't get the credit they deserve. They also have a "cool factor" in terms of appearance and powers. It also helps that X23 belongs to this generation.
I loved Generation Hope probably more than most people. The "Lights" was a great concept that deserved to have its own series. I liked the entire cast except for Primal. These characters, aside from Idie, are even more buried than the Academy X characters. It's a shame because they served a thematic purpose and Kenji and Laurie have great designs. They really should have been the ones to usher in and guide the rebirth of mutants. They should have been involved with Hope and the Phoenix, and probably should still have something that makes them unique. Marvel put out 17 issues with these characters and then totally dropped them.
The JGS kids represent a lot of annoying fumbles, mainly AvX and its aftermath. I appreciate the book for bringing a lighter tone after years of grimdark, but it didn't have to sacrifice the trajectories so many characters were going in to do it. Out of this generation, I'm fans of Idie and Kid Apocalypse and Bendis' kids (who are more like a separate entity because they aren't Aaron's creations). I loved Bendis writing for Tempus, Triage, Goldballs, Morph, the Cuckoos, and the O5. I still think the JGS kids are ok but they don't have a lot of substance and Marvel just doesn't care about these students or new characters. Hopefully Disassembled ends the nostalgia fest that prevented any new characters from getting development.
The Cuckoos kinda count for all these generations. It's nice to see them aged up and take on a non-student role in X23. I'm still confused about if characters like Anole are graduated yet.
Morisson's students are amazing and they are amazing as the special class. I think they belong in this world and should be used more. Martha alone makes me want to vote for them.