Please find below table for some of the differences between IE Plugin and Ajax client modes.
|IE Plugin||Ajax client|
|Users can resize screen to fit||Need to install Extension for this.|
|Macros can be executed.||Macros not available|
|Close fit to desktop view of document||Object positions and size can vary compared to desktop client|
|Supports only in IE.||Supported on various browsers|
|Plugin has to be installed on each client||No installation at client|
|Extension objects won't work.||Extension objects can be used|
|Session collaboration & Notes and annotations is not available||Session collaboration & Notes and annotations|
|Plugin has to be uninstalled & reinstalled when server is upgraded||No installation required.|
|Print Sheet is available.||Print Sheet is not available.|
|Bookmark More option is available||Bookmark More option is not available|
|User Preferences option is available||User Preferences option is not available|
Please feel free to let me know if I missed anything in this.