Choosing new phone/carrier - Advice?

I've been looking into getting a new phone and I currently have MetroPCS, I was looking on their website and it looks like for a decent phone I'll be spending about $100-$150. I looked into switching to T-Mobile to see which would be cheaper. I'm currently paying $50 at Metro for unlimited. The phones I've seen through T-Mobile were much better than the ones at Metro, and T-Mobile has a thing going on where you pay so much up front, then they just add like an extra $20 to your monthly bill, depending on the phone you choose, and the plans are very similar. Plus I have a 15% discount off my monthly bill for working at Walmart. So I'm really seriously considering switching to T-Mobile. The phones I have chosen are the iPhone 5c, Sony Xperia Z, HTC One, and the Samsung Galaxy SIII. I have never had an iPhone before, so I'm not sure how it is. I've always had Android. So I was thinking maybe posting and reviewing/comparing and seeing what would be best. As of right now, my top choices are between the iPhone 5c and the Xperia Z. Any advice or info will be appreciated. Thanks!

via Forums de téléphone cellulaire http://cellphoneforums.net/fr/general-cell-phone-forum/t365971-de-choisir-un-nouveau-t%C3%A9l%C3%A9phone-transporteur-des-conseils.html