appel or android

The main difference between these are the size and app stability.

Iphone 4s

Pros:

Apps are stable
Apps appear first on ios than android
Phone is small compare to today's standard - Good for portability
Good camera
Performance is good for games and general multitasking
Very secure

Cons

Small screen - Not so good for watching video
Expensive if broken
Difficult to maintain - Can't upgrade on storage once phone is bought
Bad battery life
Very little customisations available

Nexus 5

Pros

Good screen for watching videos
Get the latest version of android as they are released
Has stable apps although some can crash if they are in the beta stages
Performance is good for games and general multitasking
Customisable
Cons

Has an ok camera
Possible to get malware but this is rare
Can feel cheap
 


Of course Nexus 5. I will describe you by comparing the both.

Nexus 5 and Iphone 4 pros and cons
Nexus 5 have 2.3 Quad core Processor, where as iPhone 4S have only 1 Ghz dual core.
Nexus 5 have powerful GPU as compared to 4S.
Nexus 5 Have better display as well as display Glass i.e. Corning Gorilla Glass 3, that is strong and scratch resistant.
Nexus 5 have better battery 2300 mAh, Iphone 4s only 1432 mAh. (Both phones have non removable)
Nexus 5 have 2 GB RAM and iPhone have 512 MB RAM (just forth part as compared to N5's RAM). It means N5 will have better multi tasking and more apps it a time.
Nexus 5 will get future android updates faster, Iphone 4s is Discontinued product and it won't gonna receive updates.
Nexus 5 have better camera I think so.
Nexus 5 4G supported.

I don't know what pros I tell you about Iphone 4S, you compared a elephant with an ant hehe. Iphone 4S is older device and is a waste of money in my opinion. 3.5 inch display will make gaming controls very hard and bad experience of video watching. I highly recommend Nexus 5 in this case.