I changed out the ch751 locks not because of security, but because the keys are flimsy zinc/brass construction and tend to break. Amazon has "automotive grade camlocks" which are generic double-sided locks that have a shutter to keep out dirt. These have worked reasonably well.
I found a place, lsidepot.com, that has Medeco and Abloy cam locks for $20-$25 each. I might go this route, not because the locks will be more secure, but because they will still be working a long time from now, and they can come with dust caps.