Need help deciding on what to do

I'll give you guys the quick run down. I'm not that brilliant with droids, but I know what differs a good droid and a bad droid. I had the LG Revolution which made me realize what a bad droid was and had an upgrade from my line ready. I upgraded to the Samsung Stratosphere mainly because it was free from my local Best Buy and I have no funds right now. Turns out my sister, who has a Motorola Bionic, really really wants the Samsung due to the full qwerty keyboard(all she does is text). So basically she wants to trade phones. I have heard some stuff about them both saying they are somewhat touchy phones. I've never had a Motorola and I don't know what Motoblur is, but I don't know if I would like it or not. Question is...should I just swap phones with her since it was free in the first place(her's is around a month old), or should I take it back since it hasn't been 14 days yet and fork out the money for a Charge or any other phone like that? Thanks for any and all info.