We are considering adding geoprocessing services on our ArcGIS Server infrastructure, and wondering what others' experiences were. Effect on performance is the biggest concern. I realize there are lots of variables there, but a specific use case would be a service which buffers point data. We currently have a single server site but expecting to bring a second server online soon. Alternatively considering using ArcGIS Online geoprocessing services, although that consumes credits. Wondering what others have done. Is there a reliable way to estimate performance impact, given an anticipated use case?