I am working on a big legacy application written in Delphi. Most of the components are VCL and DevExpress QuantumGrid components. I would need to update the UI to support various styles and a more modern look and feel. Originally I was planning to switch to the DevExpress ExpressSkins library (I already have the full DevExpress VCL subscription) and replace all components with DevExpress components. However since than I have upgraded the project to Delphi XE2 and with it came the VCL Styles technology.
What are the pros and cons of these libraries?