I found the free version to be pretty much unusable with its limitations; think of it as a seriously limited demo. But once I bought the software I really love it! It can produce absolutely amazing vocals that are indistinguishable from a live singer!

The GUI has a few quirks but all in all it is pretty solid (not nearly as quirky as BIAB!)

One tip: if you buy the paid version, before you install it be sure and completely uninstall the free version first. I found that the free version was not completely replaced by the paid version and certain features, like working inside Reaper, did not work until I uninstalled both free and paid and then reinstalled paid!

After you get the paid version. I recommend going to their YouTube channel and finding the set of videos that are in English (if that is a language you are comfortable with.) Those 10 or so videos took less than an hour to listen to and got me up and running nicely!

One more tip: I have gotten the best results by using Synth V to convert my vocal track to MIDI for use in Synth V. I just record my vocal track while listening to my BIAB backing track. Then I bring my vocal track into Synth V as well as my BIAB backing track. Synth V will convert my vocal track to MIDI and then I assign a voice and make any tweaks needed.

Cool tip #3: join the Dreamtonics forum and participate. There are folks there who know the program quite well.

Tip #4: check out the user-created scripts available for Synth V! There are some cool ones that really add to the program. My favorite has been a harmony script that will take your vocal MIDI track and create another vocal MIDI track with your choice of harmony parts! (Not perfect but a good start for creating harmonies!)