I'm actually reading the Argonautika now, as it happens.
If you're finding Homer difficult, I'm afraid you won't find the Argonautika much of an improvement. I think the grammar/morphology is a bit more regular than in Homer, but stylistically the Hellenistic poets tend to be challenging. Apollonios is writing very much with an awareness of epic conventions, and he plays with them, expecting his audience to recognize the allusions. He does use the occasional formula, but not nearly as frequently as Homer. There's also a general tendency to show off his erudition.
The narrative is much more varied and unpredictable than Homer, so if you're simply losing interest in Homer and want to read something else, you might find the change useful. However, I know that for me part of the difficulty with the Alexandrian poets is precisely this variety -- you never quite know what to expect next. I find it much easier to come up with the meaning of a word that I almost remember if I know that, oh, yes, we have an arming scene coming up, that must mean "shield".
I don't want to turn you off if you really want to read the Argonautika, but you should have some idea of what to expect.
If you're looking for a good story to keep you motivated, I might suggest Lucian of Samosata -- he wrote some very entertaining (and wild) satires and parodies of travellers' tales. We read selections in an intermediate Greek class, & there are a couple of student editions with helpful notes and vocabulary. (eg Keith Sidwell/Bristol Classical Press).
IPHIGENIE: Kann uns zum Vaterland die Fremde werden?
ARKAS: Und dir ist fremd das Vaterland geworden.
IPHIGENIE: Das ist's, warum mein blutend Herz nicht heilt.
(Goethe, Iphigenie auf Tauris)