Iphone or ipod for working out/gym time??

I have the iphone 5, I used my iphone 4s A LOT in the gym, because I love Pandora, but I know I sweat on it a ton- I did not use the arm band because it felt tight, so either I held it, it sat in the cup on the machine or set inside my sports bra (i know, I know). It did have a protective case on it and screen protector on it at all times.

Which is better for working out, not just running, iPod or iPhone? Thanks! I do listen to Pandora a lot, but I also listen to my itunes collection.

I also do not mind buying another APPLE product. haha. I have the iphone, but I would totally get an nano or ipod touch.

Thanks for any and all insights!