I want to upgrade my almost 10 year old classic 350. I'm confused about the new Triumph T4, scram 440 and the Guerrilla 440. My budget is expandable and my daily commute is around 40 km. I want a comfortable bike with minimum maintenance. My ride will mostly city with occasional highway touring. My main priority is comfort and ride quality. Please suggest a good motorcycle.

Of the three bikes you have shortlisted, we would suggest you choose between the Triumph Speed T4 and the Royal Enfield Scram 440. These two will be more comfortable, although the Royal Enfield Guerrilla will give you more performance on the highway. 

Since you've already owned a Royal Enfield Classic, the latest Royal Enfield Bullet / Classic is also worth taking a good look at because they will offer you good comfort and ride quality - both of which are important to you. 

You can alternatively also look at the Honda CB350 models because they are comfortable, smooth, well-built and torquey. 

A test ride of your shortlisted bikes will help you decide which is the best option for you.