Which is Crueler?

Studies have shown anywhere between 10%-30% of all the feline participants declawed had developed behavior problems. Depending on the location from which they were removed, around 10% of the participants had also shown signs of lameness in their paws. While the studies' exact percentages may be subject to question, there's no denying that (if you wish to believe) little fraction who have been negatively effected by the procedure.

Source: I love cats (especially my own) and read a lot about them, and I've volunteered once-to-twice a week at a local animal shelter for several years.