I used ProSeries for many many years i.e. greater then 25 to do both personal and business returns but about 5  years ago I migrated all of the business returns to Drake because ProSeries prices were getting ridiculous.  Since I purchase the complete Drake package each year (which is way less than ProSeries wants for just the 1065/1120 package) I tried a couple of personal returns on it for clients who are in a hurry to get their returns filed bcause they are leaving for warmer climates.  I got them e-filed on the 26th with absolutely no problems.  Needless to say this is my last year for ProSeries.  And, I am now starting to use Drake accounting this year so goodbye Quickbooks also..