Karin needs to be herself and do what she wants to do. She is so talented and charismatic that the worst thing she can do is follow the bored solo-style UFA has. She has to do the music she want and be the funny crazy bitch she is. That's all.
Only if there is a company that is willing to invest in her. In UFP it's safe but she won't advance much, but outside UFP she has to govern her own problems (from singing, choreography to finding appropriate music label, managing own budget). Both choices have their own advantages and disadvantages. Let's wait and see how Riho did outside of H!P first. However, I believe that Karin's fanbase is stable and won't decrease much after she leaves, which is an advantage for her. Every success has its own hardship, though.