Oh boy... Ener-G, IB, EP, E-Power.... Where will it end.
Personally, I am very happy with the EP cells. Sounds like the Ener-G cells are well liked. The New IB 4600s should be good but time will tell the reliability tale - same with the Ener-G cells.
Every battery is claimed to be the best when it comes out. All of the supporters of company X will say their batteries are the best, A battery will win the big race and everybody will go buy that thinking that they will win too - it helps if 80% of the top drivers are being sponsored by that battery.
It can be hard to sort the hype from the reality when there are so many people that are loyal (financially/sponsorship/selling) to a company and will tout their products all over the net.
ALL of the new cells are pushing the limits of capacity vs cell size.
Also, remember that cell manufacturers are different from the matchers. 5 matchers can all be selling the same cell so theoretically they shuold be just as good if the matcher did their job right.
Finally, the more drivers a company sponsores the more of the best cells that are not available for you to buy.
Sorry if I ruffled any feathers.