I started noticing this on WOZ with long games. Flippers would get sluggish to be noticed. I put some fans on the coils and now that never happens.
They do still "feel" different than a modern STERN or a B/W or an EM for that matter. But the sluggishness from heat seems to affect all modern games... How come the B/W games never have problems with sluggish coils? Was Fliptronic that much better?