According to my experience 2200 mAh is the best. It has 20 percent more battery life as compared to original PSP battery pack. But try now to buy second hand or used batteries because they wont run for long. Specially don't get the batteries from online sites like eBay. Because one can not test these batteries and these batteries don't have a guarantee. So always go for branded and tested one.
Enjoy blurting :)
Enjoy blurting :)