We're 99% fresh reload. We're almost entirely residential, and most of our customers come in only when the drive is totally messed up. We used to do clones for a little while, but it'd bring over tons of other messed up stuff we'd then have to call and ask them to pay us more to fix. Now we only do it if there's a specific reason to. We also just use Disk Jockey Pro, super easy cloning.
The only times we ever had issues are when people don't have their Office install media/product key, but we can usually get around that complaint by offering to install one of the free alternatives (again, we're almost entirely residential customers, so it doesn't matter much do them).