Both bikes that you have shortlisted will be excellent companions for your long daily run. Both the Honda CB350 and Royal Enfield Hunter 350 have smooth, torquey engines, upright seating ergonomics and a plush suspension setup. If you are a taller person, you may feel a little more comfortable on the CB350 because it is a larger machine than the Hunter, although the RE isn't exactly cramped. 

In a similar price range, you should also take a look at the Hero Xpulse 210. With its long-travel suspension, peppy engine and commanding ergonomics, this could possibly be the most comfortable bike to tackle long distances every day. Its seat height - at 830mm - is on the taller side, but if that's not a dealbreaker, we'd strongly recommend taking a look at it. 

A test ride of these three will help you decide which is the best option for you. 

Between the Royal Enfield Classic 350 and Meteor 350, the former would be our recommendation. The Meteor's feet forward position will transmit more jolts to your back over bad patches of road. Therefore, it won't be comfortable over long stints in the saddle. The Classic's upright and neutral rider's triangle will be easier to live with on a day-to-day basis. 

You should also take a good look at the Honda CB350 models because they have a similar riding experience to the RE 350s. But are much lighter and come with alloy wheels and tubeless tyres. They also have a slip/assist clutch, resulting in little effort when operating the clutch. 

Since you are a taller person, looking at an ADV like the Hero Xpulse 210 and TVS Apache RTX 300 is also a good idea. Of the two, the RTX is the better all-rounder, but the Xpulse is lighter.

Take a test ride of these bikes so you can decide which is a better fit for you. 

The Harley-Davidson X440 will be a good starting point for a novice rider, although you will take some time to get used to its weight. Since you are shopping in this class of bike, other options to consider are Royal Enfield Hunter 350, Honda CB350 trio and the TVS Ronin. Of these, the Ronin will be the lightest and one of the most affordable options while still delivering comparable performance to the 350s. 

The Yamaha Aerox 155 is a good scooter in many ways, but its stiff rear suspension and cramped ergonomics for taller riders are two big reasons we would steer you away from it. If you do want a large-capacity scooter, then the TVS Ntorq 150 is our current pick because it has engaging performance but doesn't sacrifice comfort or practicality. 

Take a test ride of everything you consider, which will help you decide if you're ready to get into bikes or should stick with a scooter. 

Since you already own a Unicorn, stepping up to the Honda CB350RS is a logical move. The CB350RS is a reasonably comfortable machine with a smooth engine and should offer you more riding comfort and enjoyment than your Unicorn. That being said, it is worth checking out its siblings - the base CB350 and the CB350 H'ness - because all three, while mechanically very similar, have different riding positions and price points. We would recommend getting the one that you find the most comfortable on account of your long daily commute.

Other options also worth taking a look at are the TVS Ronin and the Royal Enfield Hunter / Classic / Bullet 350. These are comfortable, reasonably fuel-efficient and reliable bikes which will be a good fit for you. 

A test ride of these will help you figure out which is the best option for you. 

Since you have already owned a Honda motorcycle in the past and are familiar with the ownership experience, the Honda CB350 makes for a logical step up. This is a smooth, comfortable, reliable and decently fuel-efficient machine which should serve you well over a long period of time. 

If you want to look outside the Honda umbrella, the Royal Enfield Hunter 350 is another great option to choose. The Hunter will feel lighter, more manageable, while retaining similar strong points to the CB350, like the torquey engine and comfortable ride quality. 

The Royal Enfield is also a good chunk more affordable than the Honda, which is something to consider, too. 

A test ride will help you decide which is better for you. 

Considering your usage and budget, you can look at bikes like the Royal Enfield Hunter / Bullet / Classic 350, Honda CB350 trio, TVS Ronin and the Hero Xpulse 210. All have spacious seats, comfortable suspension and have decent braking performance too. A test ride of all these machines with your wife sitting behind you will help you decide which is the right fit for you. 

Do bear in mind that making the switch from a scooter to a motorcycle will need good hand and foot coordination to operate the clutch and gear pedal.  We recommend you practice on a used bike first before taking the plunge. 

If you want to stay in the same displacement range as your Unicorn, you can look at the Bajaj Pulsar N160 and the TVS Apache RTR 160 4V. Both have great suspension, peppy performance and will return similar fuel economy to your Unicorn. 

If you want to make a step up, then bikes like the Royal Enfield Hunter / Bullet / Classic 350, TVS Ronin, and Honda CB350 trio will make for good commuting partners. These are bikes with upright, neutral ergonomics, plush suspension setups and torquey, smooth engines. Expect lower fuel economy in comparison to your Unicorn, however, by virtue of its larger displacement.

Lastly, the Hero Xpulse 210 is a wonderful do-it-all machine which will have the best suspension comfort of all the bikes listed here.

A test ride of all of these bikes will help you determine which one is best for you.

The Honda CB350 and CB350 H'ness are essentially the same bike wearing different outfits. The former mimics the design language of the popular Royal Enfield 350s, while the latter has a distinct Honda design. 

As such, their riding experiences are going to be exceedingly similar and picking between the two will come down to which one you prefer the look of. 

Coming to your query, both these bikes offer good pillion comfort and are good to ride in dense city traffic with their neutral handling and light clutch action, thanks to the slip/assist clutch.