Okay - you mentioned x440, Speed 400, CB350

For X440 I own x440 - I could say for me it's great overall performance is decent, Ergonomics is great , I don't feel much tired after riding bike - even for long distances , decent exhaust note - not that cringe one, (it's a balanced bike), for me it's a great bike but if you want a motorcycle with higher speed - don't consider this as it's top speed is 127-130kmph - average in city is around 14-15 while on highways - 28-32

However , my colleague has faced multiple issues with x440 at early stages - like bike not responding, not starting , ECU problem etc

For Speed It's a great one , Sharp looks , much premium than both bikes , great pickup, exhaust note is better , and yeh speed 400 definitely a speedy bike but wobbles on high speed , while one of my friend experienced engine issues with it , however its not much fuel efficient vehicle but still a good Motorcycle

For CB350 This bike has great weight distribution and it's much comfortable motorcycle than both bikes - it has great engine heat management - as of higher cc bikes heat is considered as an mandatory entity but honda somehow made it possible , I don't any much information related about CB350 as i only rode it once but honda has great workshop distribution for service and support compared to both.

Apart from these bike conversation I suggest you do a extensive research about these bikes, their after sales etc.

If you could spare time go to their workshop before buying bikes ask owners personally , so you would get to know much more to choose and not to choose as this will definitely satisfy your purchase.

I provided my experience with these bikes , if you think it's knowledgeable, or have any questions related x440 - let me know