I have Logic but don't use it. I think if I did I'd use Redmatica's joint for chop'n samples rather than this method. From what I've read Redmatica allows u to do more manipulating of the sample.
What Just did is still a good solid way of getting it done.
I can do the same thing in Ableton but faster. Maybe because it's what I use on a daily. I use slice to midi, set my warp markers and it's done. Instead of poly, I have the "choke" feature which works the same ( cuts off the previous sample ). I actually think Ableton gives you more control over cutting off the sample because you have the ability to assign certain samples to 16 diff't choke "groups". Meaning only the samples in that certain choke group will cut off the other samples in that choke group. If I'm not mistaken what ever samples you have in the EXS use the same poly setting. It gets the job done but if you really want to manipulate things beyond imagine Ableton affords you that possibility. I don't sample much but when I do Ableton gives me "crazy" ways of manipulating them.