Electrum is good and a pioneer, but Sparrow really feels like Electrum on steroids. Some of the things that come to my mind:

• really nice transaction visualisation, allowing you to really understand what you're doing, do proper coin control, etc. You can do this with Electrum, but I just like it better the way its done on Sparrow ;
• doesn't connect you to a random Electrum server on the firsts start ;
• has coinjoin capabilities ;
• lots of work on interoperability (e.g. making it easy to import/export wallets, as this new release also shows).

I am not saying you should ditch Electrum (I still use it sometimes), but you should definitely give Sparrow a try :)