Uploading #PowerPivot for Excel workbook using "Save As" vs. SharePoint UI

When you save a PowerPivot for Excel workbook by using the “Save As” function with Excel, this will use the Office Upload Center as its mechanism to save the file.  This is different than uploading the file by using the SharePoint UI as the SharePoint UI uses a different mechanism via http to upload the file than the Office Upload Center.  The Office Upload Center is included as part of Office 2010 and what is great about this feature is that you can save the file asynchronously.  What this means is that you can save the file and then continue to work with your Excel file in the mean time.  With the SharePoint UI, once you upload the file it is locked and you cannot work with the file until the upload has been completed.  Though, based on current sets of tests, the upload via SharePoint UI is faster than the upload via Office Sync Center so there is the balance between whether you want to work with the file asynchronously or do you want to have faster upload.