Google Hangouts has the same feature. There is an icon below the last message the recipient has read.
While on Hangouts you can also see if someone is in the middle of typing you a message but hasn't sent it yet.
What's also nice is you have the option to consolidate your SMS and Hangout messages in one app and easily switch back and forth within the same conversation. For instance you can start a conversation using Hangouts over WiFi, drive somewhere in your car and continue the same conversation over SMS (not while driving of course).