.380 is becoming a lot more popular for many reasons, but each model is a compromise based on your intended use. For me, whether or not I'll actually be able to use it effectively is the first priority, so on the bike it has to be as small as possible (for me). I'm not aware of any 9mm that is even close in weight to the Ruger LCP .380 (like 10ozs), so you are going to have a 9mm brick in your pocket. Also a stray .380 shot is less likely to hit/kill an innocent bystander, and it's easier to aim/control in theory. Pretty much same round size, less powder. So only intended for under 10yds ideally (which most roadside conflicts would be). Just trying to stop someone from attacking, one decent shot would more than do it. 9mm may be more be ideal... but if it's too heavy/awkward to carry/draw on the bike, then that won't help. A tiny .380 is the only pistol I would consider riding with, otherwise I wouldn't bother carrying at all. If the 9mm doesn't bother you then carry on! (see what I did there? :-) ) Just my personal opinion