Some more things to be considered if one is in the process of chooing a 22 Hornet or something else:
The Hornet was the first of the new breed of super fast varmint 22's. It was invented by Wotkyns around 1929 and was based on an old Winchester case. Wotkyns was so impressed with his new round that he got Col. Whelen of the Springfield Armory interested in it. The first rifle that Springfield made for that new round turned out to be the most accurate cartridge/rifle combination that the illustrious old armory had ever produced. Whelen was now so impressed that he got Winchester to put it into production, both rifles and ammo.
This little round started a flury of activity that within two decades or so resulted in the introduction of faster and faster 22 varmint cartridges, most now foregotten: the Wasps and the Bees and Zippers, etc. which finally lead to such impressive numbers as our present 22/250's and 220 Swifts and then the introduction of the new cartidrige family of the .222 Rem. and .223, which you currently own.
One would think that the Hornet would have been left in the dust, but that didn't happen. Instead, as performance got better and better, the Hornet began to fill the void left between the 22 LR and the faster rounds. Today, it is often thought of as filling the gap between the performance of the 22 LR and your .223.
The Hornet has some strengths in filling this role. It probably was the little 22 that was made in the greatest numbers and ammo will be available in more places than any other cartridge in its class. Not only has the Hornet been made by just about every manufacturer at some point, but several still do. It is made not only in this country, but abroad as well. CZ and Anschutz (I think?) are making rifles for it right now. So it is known not only in this country, but around the world. I have even heard that in some countries it is illegal, as it is thought of as a poacher's weapon, but I do not know if this is really true.
So, this cartridge has some advantages.
It also has some disadvantages. If one were to try and invent the perfect cartridge to fall between the 22 LR and the .223, one would be unlikely to choose the 22 Hornet case with its old fashioned long taper. A blown out case with a little extra capacity would probably be choosen. The Hornet is best with 40 and 45 gr. bullets, and one might want to go a little heavier. The Hornet brass is rather thin, and some people think it is hard to reload. I have only reloaded it in hand dies, and even then, I crush a case very now and then. I can only imagine that if one tried to run off batches in a more efficient manner and everything was not set up just right, it could really be a frustrating mess.
All in all, Hornet has tradition, acceptance and availiblity going for it, while a newer round in this class should actually do better in several respects if its designer had any sense in these matters. It should not be hard to beat a 70 year old round.
It all depends on how you weigh these things in your own mind.