I think the leather looks nicer, and people like it better because it'* a richer look. I personally don't like it in the summer, as I wear shorts most of the year, and in the winter, it'* a little slippery, which I also don't care for. Like many americans, I'm a wider than normal guy, and the buckets are skinny friendly only, and not comfortable on long trips.
As for cloth, I believe cloth is much more comfortable, especially on long trips. My '92 had the 60/40 cloth seats, and had the column shift, and my 94 had the seperate 50/50 cloth, and I loved those as well. they were both comfortable, and the look isn't bad at all. My '94 caprice also had the 60/40 cloth, and I can drive on a thousand mile trip, with no pain to be mentioned.
I think the leather is more of a fad, than anything else. I think most people like leather for the richer look, and nothing more. But, I'm wider than the leather, so, I'm probably not as comfortable as most of you, and we have to take that into consideration..
I will admit the 9 way power seats allow a lot of choices to get some comfort, but I can never seem to find the right setting, and when I do, my wife changes it. lol..
If I'm driving aggressively, the 9 way power seats tend to hold us in place better. Maybe the leather are good sport seats for those who race around, and do lots of shorter trips, but I think they are uncomfortable on extensively long trips.
I guess my vote is to keep the cloth if you are comfortable, and do long trips, and go for the leather if you are into the richer look, and sporty feel in more agressive driving.
I believe both have their place, and it'll depend on your personal preferances, and needs..