Is there any difference between SANYO's eneloop XX and Panasonic's eneloop pro? Can I use old SANYO's charger to Panasonic's batteries?

Besides the change to the name (Panasonic bought Sanyo) and changed the name from XX to Pro as well as the packaging, the only real change is to the number of charge cycles the batteries are rated for (up to 500) and the milliamp (2550 versus 2500 - a bit longer run time between charges). Yes, you can still charge these batteries with your charger or any fast NiMH charger.TammieThomas Distributing

This seems to be among the highest capacity AA batteries out there. Are there any other NiMh AA's that have higher capacities?

Not any more.. PowerGenix had a Nickel-Zinc (NiZn) AA Battery that was but it still did not compare to the eneloop Pro / XX line. Remember that the eneloop Pro only has a 500 Cycle Life compared to the eneloop with 2100 Cycles.. But the Pro is a Higher Capacity Battery designed for devices like High Power Camera Flash's, RC Toys, High Draw Lab Equipment, Wireless Mics Etc.

How long does it take to fully charge batteries with my eastshine s2 charger?

The question is between a "full charge" and the average voltage for the battery within a single discharge. To go from 1.10 volts to 1.5 volts or whatever may take 8 hours but to go from 1.10 volts to 1.28 volts (close to a full charge) requires less than an hour. The charge rates are actually deceptive considering a lack of memory effect for partial charges.

Can I utilize my Energizer® Recharge® Value Charger with these batteries?

Yes it should as long as it came with Nickel Metal Hydride (Ni-MH). Some much older chargers (before 2006) might only charge NiCd batteries and are not suited to charge Ni-MH batteries.I would consider investing in a good charger that reads the voltage in the battery and charges it based on that. The Energizer Charger charges your batteries based on a set time and not on what the battery actually might need. This reduces the life of the battery and can undercharge or overcharge the battery reguardless of its brand. If you are considering investing in the top eneloop batteries a good $30-40 charger would be a worth while investment. Michael Bluejay's Battery Guide online gives a lot of great information about both rechargeable batteries and chargers.