I got into some Dreamcast emulation lately and managed to get some stuff working, but I notice theres a ton of different formats, so I wasn't sure what the best one would be.

I see CDI, GDI, and sometimes I hear of CHDS and ISOs but I hadn't found any of those, The ones I have are CDI cause that *appeared* to be the best one, but I'm not really sure, I got those for storage reasons but is it the worst one? Thats the one found in most places.