For a long time I used Sharepoint tasks and most recently RTM. Both of these solutions offered time stamps on notes/updates. This proved an invaluable feature as I was able to track when and how I made progress towards completing a task or project. I have been using Todo on and off for a couple of years and I truly believe it is the best app currently out there for task management. ( I would stack Things against it but there is no option to access via MS Windows). This feature is the gap that really prevents me from using Todo full time.