#1 Any I've seen are not exactly all that good looking.
As far as causing issues, it all depends on how it was installed.
If someone just screws it to the siding there may be issue with water getting in behind the siding.
I have a retaining wall in front of my house that I'm redoing with the blocks I have. The problem I'm having is I need to transition from a larger block that is 1in taller than the smaller block. Can...