Best-DMT, leaves me all warm, relaxed and fuzzly for a few hours, and the rest of the day I feel bright and sparkly and have a spring in my step all day afterwards and feel great for several days after.
Ether-just a nice, slow fading away and back again (orally, inhaled is another matter)
opiates-comedown? what comedown? just a nice glow afterwards.
Worst?
Stimulants, always hideous comedowns.
Barbiturates-bleuuerrgh, amnesia and headfuck central.
And the withdrawal from severe barb dependence, is THE fucking worst thing you could imagine in your worst nightmare.
GBL withdrawal is hell.
Worst comedown I ever had was from a combination of about 3g of STRONG 'base' speed paste, around a liter of vodka, unknown quantities of beer and cider, moderate dose of MDMA, some ether and unknown quantities of yopo snuff.
I didn't sleep for the best part of three weeks afterwards, ended up seeing voids opening up into who the fuck only knows where out of the air, and wierd arse tentacle-tendril thingys coming out.
First few days was spent wide eyed in front of the computer, listening to music, and other than that pretty much catatonic.