I am another of those people firmly of the opinion that the arbitrary distinction of hard vs soft drugs is pointless. Furthermore, I think it misleading and potentially in some cases dangerous, in certain ways. Mainly that people might be persuaded that a so-called soft drug that actually presents a significant amount of danger to a user either inherently or if not used very carefully and responsibly, for instance mephedrone and other beta-keto derivatives of PMA, people seem to class it as a 'soft drug', I have known someone to just brush it off and say 'I'll be fine, don't worry' after telling me she had done it and liked it, would do it again, and I told her of its potent vasoconstrictive effects and almost certain significant potential for cardiotoxicity, linking some BL threads and citing some journals.
And on the other side of the coin, whilst not dangerous, I don't like that misinformation and/or propaganda might put people off having a good time or in the case of psychedelics, growing psychologically, confronting issues and having the opportunity to see things from new perspectives sometimes.
As far as dissociatives go the one I am most familiar with is MXE, never had the chance to try phencyclidine, other than that, I have tried both ket, not much experience with it though, just a couple of times, and DXM which did absolutely nothing other than blur my vision and make me nauseated and vomit repeatedly. Delightful experiences, I don't think, which stayed the same regardless of weather cough syrup, cough candies or lab grade DXM HBr were used, didn't notice any negative effects that lasted from either drug, but I never had the chance to use ketamine regularly. Did get some benefit from my K use though, that I really can't explain.
Somehow, I became able to touch-type the first time I tried it, they tried teaching it with computer software in my first special school when I was younger, but I never really bothered much with it, and never was much good at it either, never bothered outside of a few hours in class here and there, years later, first time I tried any ket (dose unknown, I was given some K pills by a guy who wanted me to have a chance to try it after finding out I had been looking but not managed to get hold of any, going from my use of MXE I would say on the fairly light side of the dose range, properly active but not close to being incapacitated), I got on the computer and found I could touch type without any effort and do it well. I have been able to ever since. Bloody odd, but there you go, dissociatives can be a strange experience.
Methoxetamine...used it pretty heavily, eventually become addicted to the stuff, started using it for opioid tolerance, as I am a chronic pain patient, and found it could actually substitute for opioids entirely with no withdrawal symptoms if I switched abruptly from my pain meds to MXE, and unlike opioids its brilliant at dealing with neuropathic pain, I'm scripted pregabalin for the nerve damage inflicted by a surgical attempt to repair my knee but its only semi-effective. Insufflated it to begin with, tried plugging it, before working up the stomach to inject (I have a real problem with needles, I can't stand the fucking things....or rather, I used to

I still dislike them, especially IM but after doing countless IV shots I have no problem shooting up)
Ended up being on it most of the time, although now I have kicked the habit, used to buy in 10g lots and use until it was gone, then order more shortly before it would run out. Did have some moments with pretty dark and depressive thoughts when I overused, and it really buggered up my ability to do demanding manual work, such as welding and assembling technical bits and pieces, the things I was welding together often turned out substandard or complete shite and needed re-doing while not on MXE, thankfully only while actually under the influence. Likewise, on a heavy dose of MXE, communication becomes difficult, speech slurred etc, and making a pigs ear of speaking in sign.
On the other hand, I find it a very enjoyable drug when used more conservatively. Ended up flushing a fair few grams I had left of a 10g bag, and dumping a large number of syringes, needles, micron filters and all but a couple of amp crackers and taking a complete break from it. Decided I am not going to buy it so often, or in anywhere near that sort of quantity in future. Just recently though I did place an order for a couple of grams and enough rigs to use it. I needed the break, although flushing the amount of MXE I did wasn't something I am happy about doing, but at the time, I needed to break the chance to give in to temptation. Responsible use is important with NMDA antagonists, they can be very seductive if one fails to keep an eye on one's intake.
I recommend using a combination of a 'racetam and choline, particularly aniracetam or better yet, pramiracetam, although piracetam is also of use, when not using MXE, as they act to increase glutamatergic activity, and in the case of aniracetam, which has some degree of AMPAkine activity its likely also to induce BDNF release and increase the expression of BDNF mRNA, promoting neurogenesis and long-term plasticity, improving memory etc. As has been noted by some on BL, the racetams seem to counteract dissociatives, which isn't surprising given their mode of action, and I can confirm that is the case for MXE.