I was impressed by the ease of use. I think the interface is easier to use than the Vocaloid 5 editor or the Piapro Studio VST. The only thing that made me hesitate to buy Synthesizer V Studio Pro was the lack of English voicebanks. They have Eleanor Forte lite, and initially, I thought it wasn't really suitable for most genres, and I have since come around--I think she does very well in specific situations. You just have to pick the right song for her.
So for the longest time, I was sitting on the fence. Then AH-Soft announced the Tsurumaki Maki voicebank--in both Japanese and English! That was the game-changer for me. I went ahead and purchased Synthesizer V Studio Pro and then bought Tsurumaki Maki AI English and also the Koharu Rikka AI voicebank. It was a tough choice for me between Rikka and Saki because both sound really good. I felt I should have one full version Japanese voicebank. And you know what? That not only gives me the option of creating songs in Japanese but also in English because the Japanese voicebanks can sing in English pretty decently!
What I like about Synthesizer V is the ability to draw parameter curves with much more control. Vocaloid 5 has the Attack/Release effects--which are great, but sometimes you want to manually draw in a parameter curve, and although Vocaloid 5 kept the parameters feature, drawing in the curves is really clunky.
Synthesizer V, however, does it very smoothly, and in the case of Pitch, you can draw the curve right on the piano scroll over the notes. That is a huge advantage.
Synthesizer V does not have a note preview though. I hope they can add that in in the future. Because what that means is that I constantly have to click on the keyboard to check the note rather than just hearing the note as I draw it in.
Most of the voicebanks have two options--Standard and AI. I prefer the AI version. The Standard version sounds more like the traditional Vocaloid voicebank. The AI version is inching ever more closely to a real human voice. The AutoPitch feature available in the AI version is KILLER. Let me say that again. The AutoPitch feature available in the AI version is KILLER.
So should you buy Studio Pro and the full voicebanks? The free versions are all very usable. If you are a hobbyist, it's fine to use the free versions. In the context of a mix, you probably won't really notice it. Well, unless you make a direct comparison to the full, paid version. There is a difference. I can hear it easily. The full voicebanks are sampled at multiple pitches whereas the lite version is sampled at only one. This means the voices can get pretty thin and raspy when you go outside the range.
Listening to Tsurumaki Maki, she sounds a lot warmer than her lite version. There is a richness in the tone of her voice that is lacking in the lite version. Again, this is not to say that the lite version is bad--on the contrary, it's very, very good. But if you want your song to sound its best (and also do commercial stuff with it), you should buy the full versions of the voicebanks.
I still have all these Vocaloid voicebanks, so I'm still going to be using them, but...it doesn't make sense to me to invest in any more Vocaloid voicebanks. Unless Yamaha wakes up and makes Vocaloid 6 AI, that is. We'll see if that happens.
For now, the future is extremely bright for Synthesizer V.
Here is a cover of We Are the People (Martin Garrix) sung by Tsurumaki Maki AI English!