Enloope is just the brand and I bought a big pack of them on Amazon for a lot less money then anyplace I have found. I also buy the same type from Target or one of the marts. You just need to watch the capacity on them and make sure they are 2200 mah. I haven't had any problems with them and I either take them to Batteries Plus and have the packs made up for me or buy the plastic holders at Radio Shack to make up some 4.8 volt packs I use in some of my small planes.
There only claim to fame is they don't self discharge, charger them today and use them next year. Other then that there is nothing special about them.