I notice that in present North American usage, at least, "of that ilk" is generally or always used in regards to negative or sinister associations, as in the dictionary quotation seen in the first reply. I have to suspect that this is because the sound of "ilk" is so similar to the obviously negative word "ill," alowing the user to sneak in a little extra jab or jibe. I've also seen "of that ilk" used in the original sense but never noticed that it has been hijacked in that way. Very interesting! And that's how English works- somewhere along the line I picked up the admittedly stray fact the original British schoolboy term "crummy" was first used to mean "top notch" or "the best!"