It seems some titles are failing to play on certain players, such as the Samsung BDP-1200 and the LG BH100. Other frustrations, aside from the disc simply not working, are long load times, stuttering and other errors. Interestingly, it seems the fault is being placed on the player itself, and not the media. As such, firmware updates are planned for affected players that will cure the issue. If only some titles are affected, however, I imagine that the media itself could have been created to avoid such a scenario.
That, however, brings to mind an important question. A non tech-savvy consumer who gets a new Blu-ray player and a bunch of movies is going to more or less expect it to just work. What are they going to think when several of their new movies simply don't function? It's unlikely they will immediately think “Perhaps I should see if there is a firmware update.” Instead, they are likely to return the discs or return the player to the store they bought them from. Will this problem get worse?