PPs which is better nich or nicd? - are they compatible?
They can be considered equivalent, good job, since NiCad are much harder to come by nowadays, and NiMH are relatively common. Packs are interchangeable, cells within a pack are not. Charge/discharge characteristics are different enough to be a pain if they get mixed.
The more mAH the better from the viewpoint of longer running (=bigger fuel tank). Performance improvement depends on how well they can deliver the stored energy (fuel analogy, you also need a bigger fuel pump and fuel pipe, if the battery has a top current limit and you find it, thats all you are going to get)
Component Shop, good place to start looking.
