2 hours is a little on the short side. Personally I like a minimum of 3.5-4 hours rated burn time on my lights. That allows for a couple of 1.5 hour long dives plus some wiggle room. But I also like the light set up I have that gives me about 12 hours of rated burn time, which is actually a lot more. Keep in mind manufacturers don't usually rate batteries at their absolute longest burn time because if it doesn't get that there would be a lot of upset customers. I have a light set up (battery/light head combo) that is rated for 4 hours burn time. I also have a double umbilical cable for that and have run two light heads off of that battery. Last week I had run the set up for 2.25 hours and it was still bright as when I first turned it on.
Really the only question you ask shouldn't be about burn time. You also need to consider brightness, ability to signal, durability, and flexibility.