I had poor luck with the Hydromax nimhs. As GB said they are only good for about one season. One thing I noticed is that the self discharge rate seemed to increase dramatically after that first year. I had better luck with the Duratrax Nimhs at about half the price.
I think also these Nimhs set on the shelf for an extended period of time before they are sold since not many people are using them so they are already on a downhill slide.
I am now out of the Nimh business and have switched to Life batteries. You can charge them fast and if you don't get to fly for some reason they will be ready for use tomorrow, or next week, or even next month. They really hold their charge.