Reply to Equipment to go with S2 ????

Hi I currently am working with a Kontrol S2 and my question is I like my S2 but I feel like there is more that I would like to do as far as effects and helping with my transitions. SO I was wondering what do you use alongside your S2? I've looked into midifighter, Kontrol F1, and Kontrol X1. It would be great if you could inform me on some pros and cons to each add on and what you would suggest or any ideas.

Thank you in advance