As a developer, it is always cool to come across software you haven't heard of, especially if it can make your life easier.
SCRIPTING SQL OBJECTS
My favorite/most used feature of SSMS Boost is the ability to script SQL objects by simply right-clicking them and selecting the appropriate option. This beats browsing through the Object Explorer Details window.
Another great feature is the ability to bring back up recent tabs you have closed out of. It brings back the state of the tab when it was last closed, edits and all.
SSMS Boost allows for the ability to format your code by the press of a button, using 'Poor Man's T-SQL Formatter'.
JUMP TO 'BEGIN' OR 'END'
A great feature tied to a keyboard shortcut is ability to jump to the top or bottom of a 'BEGIN-END' block. There are times I run across stored procedures which span hundreds or thousands of lines and all I'm concerned with is one condition in the query. It's nice to find what I am looking for and be able to jump to the condition I'm interested in by a few clicks on the keyboard.
You don't have to be an experienced developer to make use of SSMS Boost. In fact, some of its features cater to the more SQL-weary.
FATAL ACTIONS GUARD
The Fatal Actions Guard can prevent 'oh sh#t' moments from having. This can be modified to do an all-out blocking of certain SQL statements or ask the user if that's what they really want to do. One example of this is preventing delete statements without a where clause (screenshot below).
Preferred Connections is a great feature that allows the user to keep a list of specific database connections they use frequently. With this, each connection can have a unique color in the status bar (shown below in blue). It allows the user to easily distinguish what database they are currently connected to. There are also Preferred Connection settings which allow for overriding the default Fatal Actions Guard.
— Paul Krulek