4-MMC mephedrone is just great, but you have to give it some respect. It can be very more-ish and, especially if you snort it, there is a strong urge to re-dose. I have learned a lot on it, but i tell people to pay attention.
MDA don't get it. I like it, but it doesn't really elicit strong empathogenic or entactogenic effects
2-CB is entactogenic at low relative doses for me and moderately empathogenic, but higher doses are more just psychedelic playgrounds than useful for deep introspection.
I'm supposed to be trying some other methcathinones soon.