One of the superior sets of Marvel graphic novels, but it still has a good few floundering episodes. The whole series spans Issues 1-57, collected across 11 slim volumes, each largely dealing with one story. The interactions and snark between the leads are a big draw, with fun dialogue and a willingness to mock superhero conventions. There's also a more sophisticated role for Sue Storm which sees her leadership and scientific genius come to the fore, and just about forgives the decision to give her figure-hugging two piece spandex outfits even in a battle situation (but then again Reed gets progressively more muscular with a painted-on outfit, so it seems even-handed to me).
Their new origin story is handled convincingly, and returned to now and then, giving their superhero lives a feeling of real trajectory and change. The villains are by and large fine antagonists, although there's less Doom than I would have liked. After about the middle of the run it starts to feel a little aimless, with gimmicky new characters and villains/allies kind of thrown in without the writers really knowing what to do with them, and the occasional self-reflection is either handled swiftly for plot purposes (especially Ben and Johnny) or air-dropped in and not hugely meaningful (Reed & Sue's relationship troubles).
The real strength of the run is in its commitment to the appreciation of intelligence, which it shares with Spiderman to some extent, and the benefits and perils of science. The more memorable antagonists - Doom, Rhona Burchill, Zombie FF, Moleman if you insist - each counterpoint Reed and/or Sue, while the rubbish ones - Nihil, Diablo, Silver Surfer, even the Tesseract and Thanos - are based on meaningless advanced tech or hand-waving magic / alchemy.
Still, these stories zip along and if you don't like it, then no worries each one will be over soon enough. And if you do like it, it alas leaves you wanting far far more.