if u want to learn flash photography, u need to understand light and not flash. whether u use speedlight or strobes doesn't matter, it's just a preference and u need to think which is more applicable to u. i personally use speedlights because it is easier to carry around, and of course u will need to use sorts of diffusers. some will say "u want soft light then get bigger light". how come the sun is so big yet it is so harsh? try to use a speedlight for macro photography with it so close to the subject and see if it is soft or hard. For a starter, i would also suggest that u get the sb910 then play with it. understand the light not the flash then u will be able to achieve what u might want. for sure u will not stop with 1 speedlight, then u might need to buy extra speedlights or move to strobes, it really depends on what u will need. most importantly, have fun!!