We just purchased clearspace and plan to host it externally. We're a small biz and don't have the resources to host it and maintain a server in house. It might reduce the overall speed, especially for uploading/downloading files but is probably more cost effective and easier to get running if hosted externally. We will use a dedicated windows server (https://www.liquidweb.com/cart/content/dedicated/) - professional server. On our trial install it worked well and made it easy for external people to access it as well.