Indeed a part of it was off and on. I started when I was 14. I was about 6' ~165 back then so I did gain close to 40 lbs of muscle since. I've tried different variations, traditionnal 3 set full body, HIT, max-OT, superslow (that DID retard progress), J-reps. Tweaking volume, frequency, intensity, Heavy, lighter, machines, free weights... Nothing makes a perceptible difference in effectiveness, progress always comes very slowly.
Strength gains were always alright. I can chin myself with 100lbs hanging from my waist from a dead hang for 2 reps, do 6-12 reps with the whole weightstack of several atlantis machines.
The last bit of the equation I never really paid very good attention too was nutrition, I'm trying a variant of the V-diet to try and cut down to sub 10% bf, and then I'll try to follow scot abel's diet advice.
If that fails too, I guess the only resort I'll have is to shell out the cash to hire a trainer.