A priori, IF I understand how they work, I’d say cyclic is less convenient because if you’re in top (say 4th gear on a 4-speed) you can only go to first next, whereas you might just want to drop a gear into 3rd. To get there you have to go through the other gears.
More seriously if you think your in 3rd and change up, but you are in fact already in 4th, you could be unexpectedly dumped into 1st gear at speed, which is alarming and potentially dangerous.[/quote]
Standard gearbox puts neutral between 1st and 2nd gear. There’s a stop above top gear to prevent you shifting into 1st, which would be on the next rotation of the shift cam but for the stop. The neutral position on the shift cam is a shallower notch than the others, so it’s a little harder to locate, but that makes it easy to shift straight from 1st into 2nd without hitting neutral.
Cyclic puts neutral ‘under’ 1st and then there is no stop on the shift drum anywhere. With cyclic you can progress from 1st to 2nd without the possibility of hitting neutral, a little easier for clumsy feet. You can also progress from top gear straight into neutral, but going through to 1st would require two clicks of the lever. You can also if you like change direction and click back down through the gears to get to neutral as you would with a standard gearbox.
I think the cyclic was created for those who don’t want to use engine braking but would rather clog from top gear into neutral and use the brakes to stop the bike.
I personally hate the cyclic system because once in a while I will suspect I’m not in top and try to go up a gear, just to find neutral. On my Triumph I’ve cruised for an hour on the freeway before realizing I was only in 5th and still had one more gear to use. So, it’s my habit to look for one more gear just to be sure I’m in top.
By the way, it’s not unknown for manufacturers to mess these things up. The first RD350 Yamahas came with six gears and no stop above 6th. After a few people shifted from 6th ‘up’ into 1st, Yamaha blocked off 6th gear for the remainder of the production year until they had re-engineered the cam. You can imagine what happened when that bike could easily hit 120mph in 6th gear…