I Would like to highlight some points related to the SharePoint 2010 upgrade process:
Hardware Compatibility, which means that your SharePoint & SQL Server hardware should be 64bit
SQL Server version and hardware, SQL Server 2000 is no longer supported with SharePoint 2010 so you should have SQL server 2005/ 2008/ 2008 R2 with the latest available service packs. And you should note that the 32bit of SQL server is no longer supported with SharePoint 2010.
Out of the box customization, SharePoint 2010 has the same folder structure of MOSS 2007 so if you follow the best practices of MOSS customization the upgrade will go smooth with you, but customizations that been made by using SharePoint Designer 2007 is not fully guaranteed for upgrade as you may have so hiccups here and there.
SharePoint Development Customization, supposed to go smooth if you follow the customization best practices, but if you have web parts out of web part zone that will cause upgrade problems.
SharePoint Content Database Modification, if you have made any modification on the WSS_Contnet database or any other SharePoint database, that will cause upgrade problems as you should not touch the SharePoint databases, and you should have separate external database for your customizations.
Look & feel branding it’s not 100% guaranteed, the SharePoint branding has many changes between 2007 and 2010, so you may need to have some manual touches based on look and feel customization weight and the way you did that customization.
License, you need to check if your organization is covered by software assurance agreement with Microsoft then you can upgrade to 2010 without any extra cost.
Yaseen Rahhal
