Welcome!
Which one is the old one? I'll assume the left one....But yea you know. You know if you have or not you dont need us to tell you that.
I'm not sure...for what exactly. Both have their merits. Art has many applications. We need a goal to push you towards in order to have a constructive critique. Just doing the bust shot of the character and not seeing the whole artwork and its purpose or intent makes that critique entirely subjective.
You can probably decide that superiority on your own.
Well....I feel we cannot give an accurate critique then. Its kind of setting us up to be less helpful than we want to be because we dont know what the style guide is that you are trying to aim for, or follow in the end. Or if we will even get to see the finished product.
Right away comparing two styles is sort of a moot point. If you are wanting to see if you have improved and have us confirm that let us know which one was old and which one was new.
Technically...I guess the right one.
In terms of design - It follows shape language clearer and keeps the original IP's design on an innocent persona. The left one is...That's just not it. Peach is sort of a nothing burger with no personality. The head shape and eyes are the biggest difference between the two but man she was never supposed to be over s*xualized.
For it to be recognized as the OG character some aspects of the emotion and shape design have to be respected, and stylistically translated from the original. The right one does that better.
Linework and Color - The right one.
But dont let that auto smoothing line feature of whatever program you are using decide what shapes you are going to be ultimately putting into your work. There are some missed opportunities there to make a more pleasing shape with the hair or hands. Watch out for tangents.
Drawing, Value Edges and Color. Those are the fundamentals, and their order of importance.
Ultimately, you have to decide which style or process you like making more in terms of how you spend your hours. If you do this for fun who cares which one is superior? Always do the fun one.
If you do this for money, decide which one is better to enjoy while you stare at a screen all day or is more tolerable. Because the design is going to have to be more rigidly adhered too.
If this is just a post to let us know you have improved over the past few months, congratulations are in order! The right one is better than the left and you have improved. Gratz.
Later Tater.