The Honda CB350 models you are looking at are comfortable, reliable and decently fuel-efficient bikes which will last you a long time without any major troubles, by and large. Pick the one you like the look of the most or the one that’s the most affordable, depending on your preference, because all three are largely mechanically very similar.
The Triumph Speed 400 is also a great bike, but it has a much higher performance ceiling and will feel like a step up in terms of performance and handling. If that is the sort of experience you are after, it makes sense to go with the Triumph.
A test ride of both will help you figure out which is better for you.