Applications in SharePoint

I'm architecting a solution for a customer which would benefit from several features in SharePoint 2003 (Tasks, Alerts, doc repository, etc.) The solution will need several of these concepts, and I hope SharePoint's features will be a good match. However, I'm concerned that data entry pages will be complicated by the fact that SharePoint uses WebParts in zones on the page. This is similar to other frameworks I've used, yet so far I have not been able to determine the amount of additional overhead required to do data entry in SP.

WebParts are very similar to Server Controls in ASP.NET -- code in an assembly writes HTML to the output stream. No big deal from the output standpoint, but you don't get as much of the input benefits from ASP.NET controls (DataGrid is a good example).