It depends.

If you can handle your job and school work at the same time, there is no need to transfer to F1. You can go to school while you are on H1B. Unless there are some situations only F1 status can work. Status transfer now takes forever, nobody can really sure when it can be done. Since you are going from H1 to F1, be prepared to be questioned about your status histroy and why do you wanna switch.