Some say clen is overrated due to Duchaine's initial enthusiasm with the drug. He saw some studies done on animals and felt it had some anabolic effects. Unfortunately most of this didn't pan out in humans. Sure, it's still a great fatburner, but whether it's the greatest thing since sliced bread I can't say. I've found that there isn't as great a crash with clen, but Christ, the appetite suppression and energy boost are non-existent.
Ideally there would be a compound that could be rotated with ephedrine that would help with some of the withdrawal. Cold-turkeying ephedrine to rotate clen is rather unpleasant.