Selecting features with the Edit tool compared with other selection tools
When you are editing, it is recommended that you make selections with the Edit tool rather than the selection tools on the Tools toolbar (Select By Rectangle, Select By Lasso, and so on). While the Edit tool and the other selection tools all select features and follow the currently selectable layers and selection options (such as selection color and tolerance), the Edit tool has additional functionality to help you during an edit session. The other selection tools do not provide any editing functionality. The following are some of the differences when using the Edit tool compared with the selection tools on the Tools toolbar:
The Edit tool is only available during an edit session.
The Edit tool has a specialized right-click shortcut menu containing common editing commands and also has editing-related keyboard shortcuts. Although the other selection tools can be used to select features in an edit session, their shortcut menus mostly contain commands related to map navigation.
The Edit tool does not follow the interactive selection mode and always creates a new selection.
The Edit tool only selects the topmost selectable feature, whereas the other selection tools select every selectable feature underneath where you clicked.
The Edit tool has the selection chip, allowing you to refine the selection and choose the exact feature you want to select when features overlap. With the Edit tool, if you are trying to select one feature from a series of overlapping features, you can either use the selection chip or press the N key to cycle through the choices to select the next coincident feature.
The Edit tool allows you to interact with and modify the vertices of a feature and access a feature's geometry. In addition, the Edit Vertices pop-up toolbar appears when you are editing a feature's shape, allowing you to select, edit, add, and delete vertices.
The Edit tool allows you to move a feature once you have selected it. If you initially select a feature with another selection tool, you need to switch to the Edit tool if you want to move the feature. However, if you find yourself inadvertently moving features when you drag a box with the Edit tool, increase the Sticky Move Tolerance setting on the Editing Options dialog box.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Selecting_features_while_editing/001t0000007s000000/
