I really like some of the finer details in their design and can't wait for their MMD models. You can see them better
here. Granted it's a lot to take in, but I don't think these two would have benefited from a simple design.
Sugar has a marching band look and a baton. The metal on her arm warmers reminds me of a French horn and she has music notation motifs all over her. I think they could have given her some more pink and a little black to stand apart from Spicy's neon yellow.
According to the demo, their voices seem to be high quality and even have a natural personality to them, so that's great! They already sound like they have purpose and aren't soulless. I'd like to hear them sing together but I have a feeling they will complement each other well.
I've never seen anyone talk about Internet's logos. I think I like Una's the best so far.