Iphone 4 vs lg optimus showtime?

I get my phone through straight talk. I've had their 1st original Samsung phone since straight talk started pretty much. I'm thinking about upgrading. I've been looking at the iPhone 4 and the lg optimus showtime. Im little technology illiterate and my hesitation for the iPhone is the price which is about two hundred dollars more then the lg and I've heard iPhone are junk from many people also that straight talk doesn't have warranty on their phone and i would hate to buy a phone that stopped working on me after paying that money for it if the lg will give me the same perks. Please someone help me make this difficult decision with me and for me =)

IPhones are junk i wouldn't get a lg optimus, I would actually go for a galaxy s3