My choice list of dev gear is:
Enttec RDM Snifffer (great for looking at traffic and decoding packet data but timing analysis is awful)
Goddard DMXter4 (great for timing analysis, useful for generating a 1:1 NSC/RDM packet interleave with a fade running to make sure your processing/handling is correct).
Saleae Logic8 logic analyzer, which is great for getting basic timing and looking what is happening on the wire in the early stages of getting it running.
http://www.saleae.com/logic/