mostly battery issues and leaking, with gloves do you think it'll be hard to hit the button on the d530 from a head mounted position?
T.G./
Personally I have no stake at all in what lights you choose but I have not heard of either of these issue with the D550. I have 3 D550s and 1 D530 that my wife and I routinely use as primary and backup torches all of them have been down to 40 meters and the only one gave me problem and it was not due to battery or flooding. OrcaTorch warrantied the torch and allowed me to keep the defective one. I tore apart the torch and found the solid-state circuit board looked like it had excess flux on on couple of soldered connections. I cleaned it with isopropyl and was able to get the torch working again. After receiving the warranty replacement I had enough confidence in the company and the product that I purchased one for my wife.
The current D550 kits comes with 2 x 18650 rechargeable batteries. I would not doubt they outsource the batteries from another factory and just stick their label on them or contract to have their label put on them. While I have not had problems with my batteries, perhaps there was a bad batch that other folks have had experience with. Also the batteries have a protection circuit and my understanding is when the voltage drops below as certain level the battery is basically shot unless one has a specialized charger that can "wake" the battery, but I have read there is risk in doing this and it is better to replace them.
The D530 torch comes with 1 x 18650 battery and the only difference from the D550 batteries is the D530 battery has the ability to use a micro usb cable to recharge via a laptop or one can use a dedicated cradle type charger (usb recharging is super slow).
The D550 torch is either double o-ring sealed or triple o-ring sealed...I will look this evening when I arrive home from work and double check and provide an update.
I have used both the D550 and the D530 with gloves, both neoprene and drygloves. The D530 switch sits fairly flush with the body of the torch, it is not hard to push with gloves on but I have always been able to look at the switch when turning it on. If the torch does not move from the position you mount it on the side of your head, then it should be fine to locate and press, but if it does move, it could be frustrating to turn it on off with gloved hands underwater.
Both are good torches and reasonable prices.
-Z