I couldn't resist posting. Obviously Garek would win. For a few reasons.
1. It doesn't matter if Garek can't aim. Federation phasers have autoaim.
http://www.st-v-sw.net/STSWground-newphas2.html
Anyway that site analyses the technology of Star Trek and Star Wars, and in most ways Star Trek comes out on top. Maybe Han Solo will pick up a phaser, and maybe he won't... but Garek would definitely use a phaser or some Cardassian variant, and could take out Han Solo without a sweat with it. And the "friends" argument... well Han Solo has Jedi friends, but I'd rather be in Garek's bird of prey than Solo's Millenium Falcon anyday lol.
2. I remember an episode where Garek and O'Brian were trapped in an old Cardassian space station where they resurrected some Cardassian soldiers. My memory is fuzzy, but I remember Garek killing a few of the Cardassians, and nearly killing O'Brian, because he was affected by some virus. Obviously, Garek is a formidable opponent... the "Tailor" moniker doesn't do him justice, just as calling Han Solo a "Smuggler" doesn't give Han Solo due credit...
Anyway I hope this doesn't go OT, with a SW vs ST debate starting lol that would be stupid. But with Garek and Han, ignoring the technology and other factors, I think Garek would win, because he is the more ruthless of the two. Ignoring everything else, and just comparing personalities, Garek wins in the leathality Category, because he is a cold-blooded killer, and Han is a playboy.
So whatever way you cut it, Garek wins =D
Brian