I have a non-alarm
Xena X2. While the alarm would be another bit of protection, my takeaway from the reviews was that they tended to have a lot of problems. Combined with how people ignore car alarms now, I figured a simple, solid lock was better than trying to throw fancy electronics in the mix too.
https://www.reddit.com/r/motorcycles..._operator_ama/
That guy said that no decent thief would steal a bike that he couldn't ride away on. He said that people who loaded bikes into vans and whatnot were the ones who got caught.
Another tip was to put the lock on the rear wheel. It's much harder to remove the rear disc/wheel than the front. Removing the whole wheel is probably more involved than most would do for a Ninjette, but if you can get a little more security just by putting it on the other end of the bike, why not? Xena's website has a printable template to put on your bike and see which model(s) will fit your rotor. The swingarm and other parts can make it a tighter, more complicated fit (mine will only fit at one specific angle under the swingarm), but it should be more secure.