imho they are both nice, I started out on an eps 16+ but for what its worth now-a-days I would say pick up the 303.
it is not a better sampler+seq than the eps but for pairing with your other kit the 303 would serve you well. The 303
is one of the great companion pieces, i have mine hooked up to a mixer and run everything through it from records
to synths to beat machines guitars and bases, it's always useful. I do use a computer, daw software and midi controllers as well but still i say **** a computer, there will be times when you need to get away from a computer, the 303 is not overlap by anymeans, turn that **** computer off and make music with your mpc , your 303, and your ears.