This was an e-bay purchase and after reading the reviews I decided to take the top off (I would have done any way, don't we all!) to check the Capacitor vanes were in good order and the inductor connections were not damaged. It was all fine and put to use straight away.
I think any piece of kit like this needs to be treated with respect, after all it's protecting your hefty investment of the Transceiver's output transistors - matching the aerial is secondary! I have matched some horrible impedances with this but I would never run the full 100 Watts into them for fear of arcing and smoke. Not that it has, I'd just rather run QRP in those instances than see smoke.
Setting up and operation is easy - the manual is available on the MFJ site (as are all their manuals) and printing it for the shack has been handy. To make it even easier I have made the modification suggested by Phil - AD5X in this article article.

This is my method of implementing the modification, it is tight on space so you need to be careful not to short anything to the lid but the clearances here are all about 2-3 mm.

The LED wiring and general shot of the build quality...

It is a simple Wheatstone bridge matching indicator that allows me to tune-up quickly and with the benefit off being able to change the inductance when tuning (not to be done in normal circumstances!) as the maximum SWR the transmitter sees is 2:1 when tuning. 

My inverted L would never tune-up on 20 m with the LDG Z100 but with this set-up I can tune it up in less than 30 seconds with no problem at all, the LDG Z100 is great but can you beat the versatility of this tuner? I'm not sure you can! 
Martyn Jones,
5 Oct 2009, 06:15