I've found ketamine to have a pretty smooth release envelope, but I've heard people with low tolerance noting a mental spacyness that could be considered a hangover. Notable negative effects can occur it you go too hard too long with it, but the most I've done is a gram per run, and that's a pretty sweet spot for me.
MXE has a brilliant glow for a day or two...unless one keeps dosing it, which I often did, leading to a very fun and trippy week followed by a comedown of a couple days with noticeable depression and lethargy. 3meo is another story....glows for days, if not more than a week, with its long tail of stimulation that eases the body and mind back to baseline. Too much too fast can lead to a metabolite build-up which can lead to mania and a sort of fiendy psychological withdrawal while the brain readjusts. I've really only experienced 3meo comedown when mixing with other drugs, but the overstimulation shouldn't be understated because it can cause ungrounded thoughts or psychosis at worst, trouble sleeping etc.
Moderation of arylcyclohexylamines can be hard for a lot of people because a daily bump at the sweet spot can easily be rationalized by an improved sense of well-being. I have let a responsible friend hold my stash for small withdraws when timing is right. I used to do week-long runs with 3meo, but these days need to limit my consecutive uses to 2 or 3 days max, once a month.