We have been excited for the workflow process to be released. Now that it has been released, we were excited to implement it in tandem with a new model that would use the notification feature quite heavily for our approval process and to get a feel for how to best implement it in our existing models.
During the development of the model, where we had loaded the hierarchy, and little else, we enabled the process so that as new dashboards were being added, features where generated, workflow integration would be the final step prior to moving onto the next feature, dashboard, etc. of the model.
After working with workflow enabled for the level of the model that would be needed to idenify users attention, the entire model and workstation became bogged down. Things that were instantanous took 10-20 seconds. Things that would take longer (eg: an incorrect formula) would become expedentially longer as long as several minutes of non-responsiveness. Obviously, we disabled the feature with great disappointment.
We used a relatively large data set of over several hundred thousand list members, and during the testing process wasn't even using the largest list that may have been needed.