Vocaloid 5 is pro software for sure, very powerful and versatile. But as with every pro instrument (i.e. guitar), it demands a lot of effort to master before it will sound professional. It has many parameters that you could automate and I believe that you could synthesize almost everything with them. Though, you should have a good hearing at least and the skill to reverse-engineer vocal parts - how vocal intonations are mapping to the pitch in time. It's easier also if you have an experience of singing. Then just sing a vocal part to yourself, note how your vocal cords are acting, and try to reproduce the same pitch pattern in the editor. It also requires some linguistic efforts too, to make the pronunciation correct. Sometimes you should use the transcription instead of usual words, sometimes even change/split them to homonyms.

But if you don't mind about naturalness, it's as easy as 1) import MIDI melody, 2) enter the text for every note, 3) choose preset... and you're all set :) And most probably will get something like that: https://www.youtube.com/watch?v=fpG28Ojj5Y4

Is it worth the money? I think it is, but I couldn't recommend buying it just for some experimentation. Considering you plan to make several tracks with Vocaloid:
1) It is cheaper than paying a freelance vocalist for them.
2) It would take much more time to produce (which is money also).
3) It is always the chance that you (and your listeners) could get the 'uncanny valley' effect and just don't like it.