first if all i assume that they are giving me that phone for free because if i have to pay for it then the answer is just Android like the previous post but if they want to give me one for free then i will choose one

, i should mention your question is weird, black berry has many phone and you haven't said which one you are trying to choose and what budget you are talking about.
Anyway i will choose two phones and do the comparison between them, here is my candidates first from black berry Storm2 9550 and second from Apple Iphone 3GS. both come with 3.15MP camera but black berry comes with flash too, black berry screen is a little smaller than iphone but it has more resolution but in the screen iphone wins with better colors and better contrast. Iphone is 135 grams while black berry is 160 grams so in weight iphone wins again but the dimensions of both are nearly same (a little difference), also iphone screen is capable of multitouch input but black berry doesn't have that ability. black berry comes with 2GB internal memory expandable using micro SD cards but iphone comes with 8/16/32 GB of internal memory which is not expandable, so here even with much higher internal memory of iphone, black berry wins because of its expandable memory.
Connectivity options are same in both, like wi-fi and HSDPA and many other ones, cpu of black berry is not completely known but it seems to be MSM7600 which is not as powerful as the iphone one with its powerVR graphic accelerator, both have gps and both can do many things with 3rd parties apps. but now the price, the price of black berry is now around 230$ but the iphone 3gs 16GB is around 350$ which is more expensive, but any way if you pay more you get more too for better screen, cpu, design. but one important thing, remember black berry is the king in network connectivity and call quality so when you buy this phone it is a powerful cell phone with some extended abilities like camera and etc but when you buy iphone you get a normal cellphone with better extended abilities like better screen and etc, so i choose the black berry because of its better call quality and if i want another phone to use as camera and music player and other things i get an android based for those purposes.