Ultegra / DT Swiss and spare winter/commuting wheels for me.
Don't know much about the standard of that Japanese stuff( ) but from what I've read the Ultegra stuff is excellent. If that gives you the budget to also get a spare/commuting set of wheels I think it's probably worth it over a DA hub upgrade. Always useful to have spare wheels so you can continue to ride if you need a repair.
Or if you still have your FR5s in decent fettle, use them for commuting and get the DA hubs.
Although I've got the Racing 3's (which are very nice, and light) they aren't the strongest of wheels. Commuting and grotty weather I will always stick the bombproof Ventos on.