Hey go for the arc !!!
i hope you are aware of high bills for blackberry smart phones and also there are many cool apps in android than blackberry !!
but you may prefer bb if your friend circle is tooooo big and all of them have bbs
!!
arc will be gr8 for browsing also texting !!! actually everything!! a bug screen is better for games also you will find hardly any games for bb while there are games like too much for a android device like arc !!
also arc has a bigger processor than bb bold 9900 !