My $.02...
I'd love to post a vote and a quick reply to this...but I can't because the only time I've used X-Lean (which is right now), I have also used LX!!
I ran LX twice in the past as part of a pre-summer cutter. Both times I can honestly say it made a difference, I've been cutting with the same diet for years and only changing my supplementation, so I know what works and what doesn't. I love the stuff. I dosed one cap three times a day back then, not religiously, roughly every 8 to 10 hours, sometimes more frequently if I forgot if I had taken one or not.
Now...beginning November 2007...I was going to run some X-Lean alone, then supplies seem to have dried up, I only have three bottles in my stash, so I am alternating XL and LX, four caps a day (two of each per day) spaced about six hours apart. Now my OBSERVATIONS (YMMV) are that XL seems to have less of a de-stressing/mood elevating property than LX does. When I was using just LX in the past, I was always feeling good. The feeling is there now, but not so much as with just straight LX. In the summer I usually cut to look good on the beach; right now I have different reasons, but nonetheless my cut is progressing quite well. Too early to say if XL is making a difference, but so far so good. Pretty normal rate of fat loss compared to past LX cuts.
Make of it what you may...my body is a fine-tuned machine and I know how I respond to things, so if anyone wants me to "guinea pig" something, just ask...