The Honda CB350 trio are very similar machines and we would recommend choosing the one you like the look of the most. These are plush, smooth, proven and reliable machines, although don't expect too much in terms of performance from the relaxed, long-stroke single-cylinder engine. 

For similar reasons, the Royal Enfield Classic / Bullet / Hunter are also worth taking a look at. The first two will feel more substantial and have more spacious ergonomics. The Hunter will feel much lighter and more compact in comparison, so depending on the sort of bike you want, you should choose between these three.

Finally, the Guerrilla 450 is a far sportier and faster bike than these slower 350cc models we've suggested above. If this is the sort of riding experience you're after, it makes for a good purchase.  

Since this is your first bike, we'd recommend taking a proper test ride and seeing which one is best for you. 

If you want something with a bit of sporting intent in the way it rides, the Triumph Speed 400 makes for a good purchase. It is a relaxed city commuter with good suspension, a smooth and grunty engine, as well as an agile demeanour. If you want a more mellow riding experience but want a Triumph, the Speed T4 makes a good case for itself. 

If you want bikes with a more old-school riding experience, then the Honda CB350 models and the Royal Enfield Bullet / Classic / Hunter 350 models deserve your attention. 

All bikes here have been out for multiple years now and have largely proven themselves to be reliable machines. 

A test ride of these bikes will help you decide which one suits you the best. 

Of the three bikes you're deciding between, the Triumph Scrambler 400 X will be the most capable machine in terms of carrying a pillion and covering distances. This is because it is the largest feeling bike here with the best suspension comfort and spacious seats. Its 40hp engine will also give you levels of performance the other two air-cooled 350s won't be able to match. 

However, if you are a relaxed rider, then the Honda CB350 and Royal Enfield Bullet 350 will be right up your alley. Both have smooth, torquey air-cooled engines, wide and spacious seats, and good suspension.

It all comes down to what sort of riding experience you prefer. We would recommend a test ride of each bike with your preferred pillion so you can make a more informed decision. 

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.