I can only speak for the UK, and will only opine on those currently legal here.
MPA is a fantastic functional stimulant with almost zero recreational capacity, upping the dose just causes typical stimulant side effects without the good bits.
EPD is more recreational but feels like a cardiac event in powder form. With scatty paranoia thrown in for good measure!
5f-AKB-48 is a 'serious' cannabinoid, low doses are mildly enjoyable and share aspects with marijuana. High doses and it becomes an entirely different animal. Confusion, hallucinations (both positive and negative), severe panic with self perpetuating hypertension, along with serious sedation but sleep is impossible. It seems like it's trying to be so many different drugs, or that it's hitting multiple receptor subtypes. Dosage is everything.
Diclazepam is a really underrated benzo, not a great hypnotic but serious anxiolysis. Also causes pretty remarkable amnesia even at low doses. Always made me feel subjectively 'sober', but with the inhibitions of a drunk with a Xanax habit. Perfect to take with psychedelics: doesn't dull the trip or sedate you so you can't enjoy the psych, but removes all anxiety, thereby reducing 'bad trip' possibilities massively.
5-MeO-DALT - odd. Very, very odd. It is marketed as a psychedelic but feels closer to a retarded, inbred half cousin of empathogenic stimulants. Not bad in combination with a straight stimulant but terrible as a 'main course'.
aMT is perhaps the most beautiful RC I can think of, and is one of my favourite drugs in general. Has the same intimacy and emotional openness as MDMA, but without the artificial feeling of the latter. If you can get past the nauseating come up, the peak is beautiful - euphoric bliss, warm rushes, major stimulation, tactile euphoria combined with a major psychedelic element, breathing walls, text changing colour, geometric patterning and the world taking on a very cartoon like appearance. Add in the spectacular duration. Amazing.
BK-2CB feels very similar to aMT, but is much more psychedelic. Not acid level, admittedly, but definitely a psychedelic. As opposed to aMT which feels closer to a euphoric empathogen. Duration is long, again, like aMT: 12 hours plus.
It does cause significant temperature change though, in the first hour body temperature spikes, but drops to a feverish chill around 150 minutes in. Vasoconstriction is prominent, too.
Overall, a lovely chemical.
I've taken three of these compounds as I write this (MPA, BK-2CB and aMT), so make of that what you will. :D