What's better iphone 4 or nokia lumia 521?

I have a nokia lumia 521 and i like how you can pin stuff to your start screen and my friend wants to sell me her iphone 4 and i don't know if i should get it but i like the iphone 4 bc there's a front camera and more apps. Which one is better i don't know which one to get?

Don't get either, both very slow and laggy. I would say the iPhone 4s or higher, very reliable and durable, and also user friendly.

I think you go for iphone 4 because it has more features in comparison to Lumia 521.

I would choose iPhone 4 as I do not like windows phones.