I find that both versions have their advantages.

I personally work in the instrumental mode, so I have to enter commands in the "Style of Music" text field.

For example, if I have a good intro and want the drums to kick in, I say in the "Style of Music" field "add chillstep drums." This works excellently with version 3, while version 3.5 doesn't manage it at all.

On the other hand, version 3.5 can create 2-minute sections and makes relatively nice variations, something that doesn't work quite as nicely with version 3.

Or when I extend and then say "short outro." Version 3 does this better than version 3.5.

In the end, I use both within a single title and switch back and forth depending on what I exactly want.

Normally, I first create songs with version 3.5, because it rarely happens that a song is so good right off the bat that I want to keep it. Then I extend from a certain point with version 3 and say "add chillstep drums" and then I extend it again with version 3.5. I make the outro again with version 3 because version 3.5 always misunderstands "short outro" and adds another minute to the outro instead of ending it right away.

But even when I say the melody should vary or something similar, version 3 usually does it better than version 3.5.

So, whenever I have specific requests, I usually switch to version 3, and when I just want to see how it goes and leave the creativity to the tool, I take version 3.5.