I never really found slow reps, forced reps or negatives to do much for me. The thing about grindy slow reps building slow twitch fibers must be why.
To get good intensity I usually do a rest/pause set on my main lift and have started to do what Tnation calls stacking on my big assistance lifts. After years of being pretty stagnant, my assistance exercises have exploded in no time. It gives me the volume that Oni was talking about and has a progression that seems to be working. These two strategies leave me pretty wiped. Maybe not the dizzy freak out Mick was describing. But muscularly exhausted where its quite an effort to even get a soda afterwards.