I really like the YS-250 strobes for macro, for many reasons, including the same one that Steve W. cited above. The recycle time is amazing. The specifications say 1 second for a full power dump, but I have found I can do short bursts of several shots. At Seraya a few weeks ago, I was approached after a night dive by a couple (both shooters) oohing and aah-ing after watching my strobes light up the reef in rapid-fire mode while they were eating dinner. I had a feeling that major purchases might be in the offing. Much the same a few weeks later at Lembeh. The fast recycle time is great for fast-moving subjects like boxer crabs.
Many people prefer smaller strobes for macro, but I also like the additional aperture range for situations when I want to maximize depth of field. And there's no law saying that you always have to use the strobes on full power, when you want to blur the background.
I am concerned that strobes as powerful as these used close up at 3/4 or full power might be more damaging to marine wildlife, even if it is only a matter of temporarily disrupting vision or disorienting the animal. At the very least, I think it's worthwhile hanging around for a while after shooting to make sure that a temporarily blinded and vulnerable subject isn't picked off by a trevally or some other opportunistic predator.
Frogfish