Hi. Are we talking sending or receiving DMX512. Using PIC's I have used both polled and interrupt driven for my transmitters. Interrupt's let you have a more regular length then polled if you are having to do other things such as read switches.

If you use a fast enough uP then both should work well. If you are wanting to do more work eg read switches, update displays etc then interrupts are good.

Also it comes down to the persons programming ability. Interrupts can catch out the inexperienced person more then polling routines.

Hope this helps.