Testimonial: I built my visual novel game with Mannequin and released it (if your curious check my profile but beware - NSFW)!  Could not have done it without you AR14, thanks so much for this tool!

Overall, it did what I needed it to do quite well.   Easy to use, produced good looking art, and the batch mode let me pull in stuff programmatically without going crazy exporting.  Note that I am a programmer so I was able to write custom code to manage everything exactly the way I wanted - might be a bit more tricky if you're trying to get things working with renpy or whatever.

It required some creativity here or there to work around the limitations.  Most frustrating to me was that there were a limited number of poses, so to convey certain expressions I really had to dig.   Also there only being 1 body type for each gender is definitely a limitation.  Nothing wrong with the tool at all - I just want more!

If you're getting started on a visual novel or similar type game, I think you could do a lot worse than Mannequin!