bvanant
Contributor
The Ikelite has a surface guide number of 9 meters, and the Sealife has a GN of 20 or about 1.4 times as much light as the Ikelite and comparable in specification to the S2000/D2000 strobe. But in my hands at least the Inon gives me a full stop more light UW than the Sealife. I can't explain it except maybe the Sealife spec is at ISO 200. In any case, I would vote for the Inon. It is indeed a bit more (the Ike is $389 with an arm/tray, the Sealife is $350 without the tray, and the Inon is about $450 or so). I have taken mine on several big trips (Indonesia, Philippines, Bonaire) and they always just work.
Bill
Bill