Both the Royal Enfield Classic 350 and Harley Davidson X440 are great bikes to use daily, however they have a different riding experience. The more powerful Harley is also slightly more eager in the corners and has a more engaging riding position, too. It will also be less fuel-efficient in city traffic owing to its larger engine.
The relaxed Royal Enfield has a more laid-back riding position and will also feel like a slightly bigger bike. If you travel often with a pillion, the Classic is the better bet as both of you will be more comfortable.
A test ride of both will help you decide which is best for you.