Differences between Iphone 3gs and iphone 5?

I could sell the iphone 5 for 600-500 bucks and buy an iphone 3gs for 100-200 and have anywhere from 300 to 400 in cash… Honestly iphone 3gs does the same thing as iphone 5

The only difference they got is that the iPhone 5 runs faster and has more it can do. The 3GS are slower and can support some of the apps

5 is faster and bigger

The 5 of course is better & you'd be taking a good few steps backward with that move.

No 4G LTE
Heavier phone
Smaller display with much lower resolution & PPI
Less RAM
Slower Wi-Fi
Smaller resolution camera (video as well), no flash
Slower processor
Will stop getting iOS updates (perhaps before iOS 7)
Smaller battery
Quieter speakers