The mouse is inherently good for aiming. It would be unrealistic to expect anything else to perform better for that purpose... but I still think a joystick is a good idea for a flight game.
Joysticks really shine at two things: Long turns, and feel. If you need to do a very long turn in a direction with the mouse, there is two main ways it's done. One is Joystick emulation, where the mouse is typically a crosshair on the screen... allowing you to move the crosshair towards one side to turn that way (farther right it is, the faster the turn), and hold it there to keep turning. The large downside to this is that you can't center very well. With a joystick, you just let the springs bring it back to center... with normal mouse input, you just simply stop moving the mouse. The other way is to simply leave mouse input normal, which means you will have to lift the mouse (and stop moving) to reposition it and start dragging again.
The feel factor is rather obvious: It just feels better to fly a ship around with a joystick
As far as brands go, I do really like the target software that comes with thrustmaster products. It allows you to easily remap any joystick or throttle button to make any key press you want. This really opens everything up to work the way you want, since the game doesn't even have to support all the buttons on your joystick (a big issue if you have something with a lot of buttons, like my warthog's throttle), or if the game simply doesn't support joystick input for that key. For example, you can remap "button 3" (and you can click on them in a simulated image so you know which button is button 3) to tell the computer you just hit "numpad 5" instead. Apparently you could even write code in some form of the C language if you wanted something really special to happen when you hit the key.