I'm inclined to agree with what Toyz mentioned. Most of the pocket abrasion issues I've had were more related to a poor combination of the scale material being too rough and the clip being much too tight. If you refine or reduce the effect of either one of these, by smoothing the scale or taking some of the 'squeeze' out of the clip, it makes a big difference.
Another problem I've seen is with coated clips (usually black). Some are better than others, but the poorly executed coatings will sometimes rub off, especially in the high friction area between clip and scale. You end up with a black stain on your pocket. This can also be nipped in the bud early on, if you immediately take the clip off and polish the back side of it a bit to remove most or all of the stuff that would otherwise rub off on your jeans. Some bare metal clips, if they're not stainless steel (I've seen some wire clips that were made of some kind of copper-looking alloy), will oxidize and that stuff will also rub off. Most of the newer knives are using stainless or Titanium clips these days, so that shouldn't be much of a problem anymore.
I've seen a clip from one maker that was formed bent over in such a way that the screw holes in the clip were actually below the bend at the upper end of the clip. To make matters worse, the screws had relatively large heads on them, so every time the knife went into the pocket, the screws would end up pinched inside the pocket by the very tight clip. It felt like I was ripping my pocket every time I pulled that knife out. This could've been minimized at least a little bit by using screws with flush or very low profile heads.
Edited to add:
It occurred to me that I hadn't actually specified which makes I do like, per the OP's question. So far, I've been very favorably impressed with Spyderco's uncoated clips (satin or polished SS), and I also like the Ti clip on the CRK Sebenza, as others have mentioned. I don't have much experience with the wire clips, but I'd think they'd be fine. Again, I think it comes down to the combination of scale material/finish and clip pressure. Also, I wear jeans most of the time so, if you're wearing something dressier, that'll influence your choices too.