My thought on it is that there's two related issues. Personally, I'm a big advocate of the SCDJWS, as it's more standards-based (I would think) than the vendor-specific exam from IBM. However, there's also the issue of the Sun exam being slightly outdated at this point, and not in the most immediate queue as far as I know to be updated soon. So it's something of a six-of-one, half-dozen-of-the-other situation... either way, I think it shows some skill with the technologies involved.
Insofar as which is more highly recognized... I think it depends on whether the companies you're looking at use IBM or not.
Theodore Jonathan Casser
SCJP/SCSNI/SCBCD/SCWCD/SCDJWS/SCMAD/SCEA/MCTS/MCPD... and so many more letters than you can shake a stick at!