RSView32 can connect to S7-400 via OPC. I expect this to work flawlessly.
About RSView32 in general, I think that it has its advantages and disadvantages.
Advantages:
+ Really easy to make some graphics screens and add animations.
+ Some of the editing features are quite good (such as tag substitution).
+ You can expand the functionality with VBA scripts (good if you like VBA).
Disadvantages:
- Graphics are really not reusable (apart from simple cut-and-paste). Any change has to be redone everywhere.
- Relies on VBA for you to make your own functions (bad if you dont like VBA).
- The future of RSView32 is uncertain, as Rockwell is heading towards RSView ME/SE.
edit: Hey, I assumed that you meant RSView32, but you didnt state that - my mistake.
If you are considering RSView ME or SE, then what I have heard about these software packages is that they have a LOT of problems. They are genrally not finished to a degree where they should be recommended.