Swing Trainers: What, if any, do you use?

[elchene]

I was thinking about getting a weighted driver. I tried using a putter laser before but ended up returning it. It was easier and more efficient to use string to represent the line.

[GaijinGolfer]

Im a big fan of the Medicus. I used one when I first started playing golf and it did a lot to help me keep my swing on plane and with my tempo.
I think thats a big reason why Ive always had decent iron play (the original Medicus was an iron).
Now that Im getting more serious about learning to hit my driver well, Im thinking about buying the driver version of the Medicus.