Are all AA rechargeable batteries Mah rates reliable?

I found the other day a couple of rechargeable batteries i used years ago, they were like 700Mah. Recently i bought sony 2500Mah !! batteries for my camera. In january, i added to my stock some Camelion 2700Mah AA batts. but now, i began to see some chinese or japanese batteries, ranging from 3600Mah(Silverpoint) to even 4600Mah (Kayson). I wonder if these specifications are reliable… maybe they do and really last more than a 2500Mah batt, or simply not or be really a pain in the ass… did anyone try these brands? any recomendations?