Ive read that while they're all disassociatives, DXM is still a pretty different experience from ketamine. I personally havent tried the latter though, so this just secondhand information.
It is similar, but you won't go down like with ketamine. So while you are in fantasy land, you can walk, talk and interact.
It is a fun drug to do in nature far away from the city, talk to elves, clouds and trees. Just lie down, think about silly things and watch the clouds go by, it is very peaceful, almost child like. That is the good side of pcp.
In cities I can imagine it is hellish, but perhaps also adventurous if it is an quite old city with dark alleys. I never dared to do it in cities.
And when you are back, you know it was just fantasy. It is like walking into a book of Neil Gaiman. It stimulates the fantasy and makes you more open to whatever comes up. It lowers your shields of critical thinking. (And that is where the danger lies too btw, so keep notice of that)
In a hectic city that goes wrong, but in a nice safe place in nature. Even if you meet a stranger and have a talk with him, he tells you his story and you marvel in it, it is fine, it is very friendly. Almost magical.
It can be fun, but it can also bite you seriously. Be safe and watch out :) It is not as safe as ketamine and not as safe as LSD. Too much makes you look like some futuristic drunk, so you really need the get the dosage right. It is on par with alcohol (society's favourite NMDA antagonist) with the stupid things you can do on it. Only alcohol puts you down at a certain moment, so it limits the damage. PCP does not, well not enough.
Never did DMT, so can't really say. Sorry :) It is a highly personal experience, which is difficult to share with others though. I think it is similar in the sense, that you can't dismiss it. It is very real for you personally.
I am not a spiritual guy, you know? I think that makes it a bit hard to think about it. It didn't make my spiritual or anything or less grounded in my life.
I have thought a bit about this. I think the difference is this:
Ketamine leaves you in a space where you are alone, in your own universe. And classical psychedelics lead you to a space where you with others. I haven't done DMT, but I did other psychedelics in high dosages. In the end they are similar in a way.
Another way to see it: I feel dissociatives are more suitable for people who make their own values and psychedelics are more suitable for people who follow external values. I think both positions are valid and needed btw, one is just more dangerous than the other. It is easier to stray.
Classical psychedelics feel strange to me, not unwelcome, but I am in alien territory. But dissociatives feel more like home coming.
EDIT: Or perhaps they pull you to those sides. If I need to associate a term pair to the two, then chaos and order are coming to mind. Chaos is dissociatives, and order is psychedelics. But I might be wrong here, who knows. It is very subjective.
I eventually hope to write a book detailing the differences, among other things, however it will likely be years (time doesn't really exist though eh) - but if interested once I finally release it then you can email me matt@engn.com. Contemplating doing a pay-what-you-want model for it or refund provided if you've read it.
I mean nothing is like DMT but you can see some parallels with acid is mushrooms.
But ketamine is utterly different to anything else I've tried.