Depends.
If you're in a dry area, then the friction kit is probably fine.
If you get rain routinely, a belt or chain drive.
Do you want something you have to spen a lot of time tinkering with, or something more reliable? If you don't mind spending a lot of time with a wrench, a happy time kit should be ok.
Personally, I'd wait until I saved up more $, & get a staton chain drive kit.