First off, I don't have either one, but read a lot about them, and talk to people that do have them. From what I deduct, there is no comparison. The 17 will kick the crap out of the hornet every time. It shoots really flat, hits twice as hard and drifts half as much in the wind. For me that would be enough to go out and buy one over the 22 hornet. For the life of me I can't figure out why the hornet won't die... It can't do much more than a 22 mag can do, and just about all the rest of the centerfire 22's are way a head of it. Ballistically I can so no reason to buy one...IMO
Another shot fall of the hornet if you reload, is that the have the propencity to "eat" cases. The case life for a honet if you load them HOT like most people do, could be a little as two reloadings, but if you keep the pressure moderate you may be able to sqeeze 5-6 out of them. On the other hand the 17 is much less of an "eater" and case life should be about twice that of a hornet.
If you just want a close range plinker, I would get a 22mag or a 17honady mag, not a whole lot of difrence between it and the hornet out to 100 yards...
I have know idea what you are planing on using either of them for, but personally if you want a small case, I would opt for the 223, shoots as flat as the 17, but has twice the energy, and half the drift, not to mention you can find plinking load $6-8 a hundred... or just go with my favorite the 22-250.
Good luck with what every you decide
Ivan