The flash (strobe) is longer than a conventional underwater strobe. At slow shutter speeds (1/60) it won't freeze the action. For that you have to use a higher shutter speed.
I've been happy with either 1/125 or 1/250 and my Kraken 3000. My first one had a faulty strobe sensor (wouldn't fire reliably). I asked about it and a replacement was immediately shipped, including return shipping label so I didn't have to pay anything.
The replacement worked perfectly from the very first, and it's a great ring light and also a great strobe. My dives are around 72min. I keep the ring light on 25% power (white) or in strobe mode (also runs the light at 25%). So far the battery only shown minor discharge during the dive, and I keep the ring light on the entire dive. DIscharge is shown via the status light (blue = full, green = middle, red = low). So far I've barely gone into green.
I love the look of ring light macro photos, but will probably add back a strobe as I do like some fill light. Since I have now removed the wire port from my housing, I'll be using optical.
One caution, at least based on what I found. The ring light is bright enough that when I tried a DS51 with the Ikelite screw-in optical trigger, the ring light alone would continuously fire the DS51 just from the ring light (not strobe). Granted, with the cover off the Ikelte optical trigger, it's very sensitive. I had to position the DS51 behind the ring light and use reflected strobe light from the ring light to fire the flash. That's not optimal, so I bought another optical sync cord so I can connect the strobe directly to the housing and fire both simultaneously.
How it would respond with a different strobe (i.e. Inon Z240 etc.) would be interesting to see.