Whether you need to spring for APS depends upon your needs. Some very knowledgable folks posting on this forum recommend it for just about everyone due to the greater accuracy of resulting profiles. On the other hand, I've been perfectly happy with the base model (non-APS) Z3100 and its built-in automated profiling, at least for semigloss/satin papers using photo black ink. The "canned" profile provided by HP for their Hahnemuhle smooth fine art paper is visibly better than the profile the built-in spectro produced for me.
I think if your "fine art" work is mostly landscapes you'll be happy with the base model, and you can always upgrade to APS later. If you're doing work where color accuracy is absolutely critical, like fashion spreads, then it probably makes sense to buy APS up front. Just my opinion; others may disagree.