I personally prefer cdjs , to laptops , its what i know and i find myself limited with laptop controllers and feels like a less premium experience to me ,
I personally get a buzz of the potential to make a mistake , cdjs when reading of cds are nearly spot on actuate, but reading off usb they are a little more less consistent at getting the bpm correct , so youll get more drifting , so you still have to work , but with laptops they lock in perfect and its just led to a generation of djs that don't truly know how to beat match, there just reading off the waveforms being aligned ,
In my opinion that takes away the enjoyment many can pick that up with very little practice , it takes a good few years to perfect beatmatching by ear (mostly) , but if you just want to jump in straight to the set building and get your sets out there quick an interface would be a good option until your getting lots of work ,
Its about 4 grand ish for a top of the range set up , its a lot to invest in if your not certain you will use the equipment to its full potential
For now pall i would find a few friends who have decks and get a feel for all formats , and make sure your in the click with the promoters and event organisers so you can get sets when you feel your ready !!