I could probably muddle myself through it (they have a number of "bridges" to other products), but for everyone I set up thus far - if they want to spend some cash on their site, I usually suggest Threads and Photopost (if they need gallery capabilities).
Unless they are totally against either product (or want to go the free route), they have always liked both Threads and Photopost.
Coppermine in terms of code is decently solid, I am just so used to Threads and how easy it is to navigate through the code, add/change things around, etc, that Coppermine is almost foreign at first glance. I am ironically coding a front-end (albeit I am sure a buggy one) for my clients that 'just' want Coppermine and the semblance of a portal.
