It all depends on the level of accuracy, sensitivity, resolution and several other factors including on how much you can afford. So try to know your requirements first and then go ahead with purchasing the camera. You can get fairly decent images with the E Series but then the P series and S Series have 4 times better resolution as compared to the E Series. This means that objects that appear out of focus on the E Series could be 4 times clearer on the P or S series which no doubt helps a lot in better report generation. Even the fact that you can get normal digital images on the P and S series takes you miles ahead because the E series hasn't got this option.
Hope this helps.