I use it from time to time, but I don't find there is anything in ERS that you can't get from another tool so far. However, ERS can be used to modify the VB on the front end of the ICRs. But modifying ICRs comes with its own drawbacks. If you have to rewrite the whole thing anyway, you can just do all the filtering & selecting logic in crystal itself instead of messing around with the ERS project. I have also used ERS to modify ddfs in the past, but other tools can do this as well.