No, I haven't.
I'd like to learn, so an explanation would be great
Oh, really?
Caffeine: does what it says on the tin.
Beta alanine: the 750mg of BA in this per serving will - over a period of around 5-12 weeks, improve your strength (and ability to maintain it during workouts) through the accumulation of carnosine in your muscles. This is a cumulative effect that is dose-sensitive. It has no stimulatory effect whatsoever. However, supplement companies use a side effect of its dosing to claim an increase in energy and "amped-ness" which is actually neural pain, known as parasthesia (manifests as tingling in your arms and face). Dosing at 750mg MIGHT stimulate some parasthesia, but 750mg/day will do nothing for the increased synthesis of carnosine, so it's almost not worth bothering with in this pre-workout (unless you're dosing elsewhere).
L-Tyrosine: has something of an effect on blood pressure during activity, and helps working memory. No idea why/how this is pimped as helping a workout.
Vitamin B6: interesting in doses above 100mg for men (it can eliminate the refractory period - google it...
), but at 0.35mg? Pointless.
Panax ginseng: Getting good evidence for what this does is difficult because nobody can patent it. Colloquial opinion suggests this MAY help with things like working memory, etc., too, but I have a big bag of sugar here, which will also do the same thing: give me £100 for it and it will improve your workout.
Olive Leaf: Same as for ginseng.
If you are DESPERATE to take a pre-workout, find something with a sci-fi-sounding compound ending in 'amine' as the chances are this is a derivative of a quasi-amphetamine that actually has a substantive chance of improving your workout. However, you run the same potential risk (even if it's significantly and exponentially smaller) as you would with regular amphet.
Either that, or just buy yourself a box of Chest-Eze or whatever it's called, which contains ephedrine, a more potential compound with similar - but more significant - effects to caffeine.
EDIT: Most pre-workouts operate off the back of caffeine, i.e. beating the pants off your sympathetic nervous system (increases in heart rate, blood pressure, etc.) and getting you into the 'fight or flight' zone. The other bits added to pre-workouts generally do things like "maybe perhaps doing something completely unrelated in a medical/clinical trial somewhere" but nothing that would help your workout. A lot of the impact on workouts - beyond caffeine - is probably just placebo...
