I think it's faster then the default one.You should use the Open Workshop button anyway. You can't browse through new/top rated/ect addons in main menu.Limited Demos and Saves functionality - No workshop, sorting or filtering.Server browser - This menu uses the default Source Engine server browser.
Some other features that are not part of the standard menu might be added in the future. It does not have some features that I don't use. Note that this is a personal project, and it is not going to be included into Garry's Mod. It is meant for those who do not have main menu in Garry's Mod by default. A Lua powered ( No HTML ) main menu for Garry's Mod.