I had to chime in:
The biggest drawback to the Carcano is the availability, or more accurately the lack thereof, of clips. Good ones are gold; bad ones turn the rifle into a jam-o-matic....and that's assuming 6.5 ammo, which is actually fairly plentiful by comparison to 7.35 Carcano. (This is like saying snow cones are common in hell in comparison to banana daiquiris.)
The other big drawback used to be ammo, but that's loosened up somewhat in the last few years. When I picked mine up in '04, the only source was Norma. I spent more on two boxes of ammo than I did on the rifle itself. The Carcano, at least the more common variants, is still one of the few surplus rifles whose Blue Book value is substantially affected by the number of rounds in the magazine...
Also, note that if you handload for your Carcano, feeding could be iffy with spitzer bullets, even if you have good clips. Hornady makes a 160gr round-nose interlock bullet which should give better feeding (and can be loaded to give a trajectory fairly similar to the military load, which is good because the fixed sights on my Carcano redefine "crude".)
The Carcano carbines frequently came with folding spike bayonets, but I'm not sure why. I'd be afraid to poke somebody with it, lest it break. The skinny, flat cross-section blade and the latch mechanism were not designed to inspire confidence in the user. This as much as anything else could explain the WWII Italian army's lackluster reputation for close-in fighting; if you were facing Gurkhas with khukris and sword-bayonet-equipped SMLEs and you were holding this thing, you'd drop it and run, too.
They're not bad or unsafe rifles, they just suffer from some of the same defects as the Mosin Nagant design, being of similar vintage and all. A little clunky and awkward to manipulate quickly, and feeding can be an issue, but generally serviceable rifles. Of the standard-issue WWII longarms, it would definitely be my last choice to carry on a two-way rifle range.