Gave it a shot for the first time today. I didn't expect much, but I am actually pretty pleasantly surprised. I'm somewhat experienced with uppers, though I've never been a tweaker. But I have done a variety of them enough to get a good feel for them and understand their complexities and such. I've done meth probably 40-50-ish times, Adderall maybe 20 times, ritalin maybe 10-20, and coke probably 15 times or so. Meth is definitely my favorite, and coke is for sure my least favorite (and I've done very good coke - I just didn't enjoy the effects, even the part of the high that was supposed to be left much to be desired for me). I even prefer Ritalin to coke.
The reason I mention that is because I want to give a frame of reference for my verdict on this particular drug. I'm not just someone who tried Ritalin once in high school (because obviously, if I was, anything stronger than caffeine would be 'awesome'), I've actually been around the block, so to speak, when it comes to drugs. Anyhow, to me so far (it's about 2.5 hours since I took it), it's not meth but it's actually fairly close. It seems to be sort of a cross between Adderall and Ritalin, having similar qualities to both (and I personally find that Ritalin, especially IVed or IMed, can be somewhat pleasant and a bit underrated - however, it's been at least 4 or 5 years since I've done this). It's maybe even comparable to some less-than-great meth. The euphoria kind of comes and goes, unlike with meth, which keeps the euphoria pretty constant. Otherwise, all the stimulant characteristics are there. I feel awake, alert, my eyesight is kinda blurry, and I feel the signature stimulant "calm", where I basically feel pretty peaceful and content. Reading some people's reactions to it, I was surprised at how few undesirable side effects there seem to be. I'm not clenching or grinding my teeth, I'm not chewing my fingernails until they bleed, I'm not chewing on my lip or biting my tongue. All of those things are common for me to do on meth (which is even another reason I chose to keep my meth use occasional). Then again, I have yet to experience the comedown, which might be pretty nasty from what I've read.
If you're a regular meth (or even maybe just amphetamine) user, I would think that propylhexedrine would probably be disappointing. But as I rarely do stimulants (I find that they're very taxing on the body and I usually pay a price, which has kept me from getting addicted to meth despite having constant access to it - that and the price where I was living when I did it), this has been a nice treat.
A couple notes: for those who eat the cotton, I have heard this seems to contribute to the negative effects. There are some extraction methods which look pretty good, but if you don't want to bother with that and/or don't have the equipment, try what I did (thanks to someone else on some forum for the idea): I tore up the cotton into a bunch of small pieces, put it in a bottle with a couple ounces of coca-cola (lemon juice apparently works too), shook it around for 20 minutes or so, squeezed out the cotton and drank it, and I don't think I lost much, if any. I'm feeling pretty spun and that's only from 1 cotton, spaced out in 3 separate dosings over 2 hours or so. Also, about an hour-and-a-half after the first dose, I forced myself to eat a sandwich. This seems to have eliminated the whole menthol/lavender burping thing. I have been burping, but it tastes, you know, normal. Plus, I find the comedown is always easier on uppers if you keep yourself nourished throughout the experience. My worst ones have always been when I don't eat for an entire 24 or 36 hour period. In addition to the body being taxed from the drugs, it gets doubly taxed from not having any fuel to run on. Water is also important. Obviously, stimulants are very powerful appetite suppressants (I've had a few times where I truly could not force myself to swallow anything), so just try to choke down something at some point. You'll be happy you did. That's my advice.
And I agree with whoever said the taste is way exaggerated. IMO, anyone who thinks it's unbearable has never tried to choke down a jar-full of psychedelic cactus sludge (still one of the worst drug experiences I've had). Even poppy seed tea seems worse to me (though to be fair, that's probably due to the amount of that stuff you have to drink). I found that drinking my coca-cola drink was not exactly pleasant, but certainly bearable, and I could probably slam down 10 more if I had to.