Even in the world of rechargeable batteries, comparison shopping can be extremely difficult. The market is saturated with underpriced, underpowered, and downright dangerous rechargeable batteries. However, even among the high quality batteries, choosing the right one can be nothing more than trial and error. Naturally, all rechargeable batteries are not all created equal. Some will operate better for heavy draw devices that require large amounts of power delivered quickly. Some will work better for long life, able to produce lesser amounts of power over long periods of time. Some will be preferable for creating your own battery packs to save money. Some are better for the environment, and some have a greater shelf life which makes them much better choices for placement in emergency gear.
Really, when it comes to rechargeable batteries, there are two primary choices: the Sanyo Eneloop and the Vapex line of batteries. The Eneloop works better for devices with a higher energy demand on the battery, while the Vapex batteries are far more economical, costing a fraction of the price of the Eneloop, so they are preferred by anyone looking for a bargain.