(This thread includes os versions ,prepare for a long list)
Android :
Android is a free personalised os that gives sleek performance , however touchwiz degrades some high end devices and slows them down. The latest version is 5.1 it has the google play store , google maps and google (internet). Many different company's use android more than IOS , all at different versions. Also you can make The UI on your phone look like IOS 8. That is how free to customise it is.

Versions of android
1.0
1.1
1.5 - Cupcake
1.6 - Donut
2.0 - Eclair
2.0.1
2.1
2.2 - Froyo
2.2.1
2.2.2
2.2.3
2.3 - Ginger Bread
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.3.7
3.0 - Honeycomb
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
4.0 - Ice Cream Sandwich
4.0.1
4.0.2
4.0.3
4.0.4
4.1 - Jellybean
4.1.1
4.1.2
4.2
4.2.1
4.2.2
4.3
4.3.1
4.4- KitKat
4.4.1
4.4.2
4.4.3
4.4.4
5.0 - Lolipop
5.0.1
5.0.2
5.1
5.1.1

IOS :

IOS is a swift and snappy os , It is filled to the brim of apps and they are all very good. the current version is IOS 8.3(8.4) . However , it is more locked down and until iOS 8 you can't use 3rd party keyboards. Its name change from iPhone os to iOS in iOS 4 has marked a big change since iPhone os 1. And only apple uses iOS .

Since iOS is huge I will be putting just the terminal updates

3.1.3 - final update fore iPhone (first gen ) iPod First gen
4.2.1 - Final update for iPhone 3G and 2nd gen iPod touch
5.1.1 - final update for first gen iPad and 3rd gen IPod touch
6.1.2 -final update for iPhone 3GS and 4th gen iPod touch
7.1.2 - Final update for iPhone 4 and Apple TV 2nd gen
8.3 and 8.4 : All apple devices iPhone 4s and above , iPad 2 and above

Your a kitkat.

^^No , actually Lollipop.

King's right, youre a kitkat

':-o