Spaces is nice to have on OS X—it is just the concept of workspaces moved to Aqua. The only problem with it is that it relies heavily on the mouse/GUI side of things. You can switch workspaces easily enough with Cmd + number but moving windows around is a bit trickier. The least inconvenient way of doing this is to click on the desired window and while keeping the mouse button pressed, use the Cmd + number for the desired workspace. Hopefully next update will allow something like Shift + Cmd + number to move the currently focused window.