EMs - Gottlieb by a long way
Solid State - Bally
DMD - Bally/Williams - Special mention to Data East

I had picked up a Gottlieb King Pin about 4yrs ago but on sold it.  Kicking myself now.  I never actually got to work on it.

I have just found working on the Williams a few akward things to get into and around.  I mean the D.E's are by no means perfect.  For example, trying to put the screws (backbox) back in for the power supply.  The front hinged lamp board is completely in the way?

But on the LAH, I like the little rubber strap to hold the PF up whilst you are working on it.  I certainly dont leave my Williams up if I am more than 5mm away from it for fear of it crashing down.  

I found the D.E ramps to be more sturdy and playfield plastics much easier to remove and get in to globes.  Posts and rubbers, no different.