I know it is a bit too late for the review of iPhone 4S as we approach the release of iPhone 8 - however, I'd say, it was the best thing to happen to iPhones in 2013.
(You can grab one now for almost FREE - though retailers do not sell iPhone 4 anymore for sure.)
Just to get an idea, here's something from MacWorld ----
The iPhone 5 was dropped from Apple's iPhone line-up with the launch of the two new iPhones, iPhone 5c and iPhone 5s, but the iPhone 4S lives on, and is a cheaper alternative for those who are happy with an older iPhone if it means a lower price.
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Still some limitations - not a great camera and bulky or heavy. Hey, it was still a good one at that time!