I've had barbital before, as earlier stated its used as a buffer in biology labs. Its one of the longer acting barbs, like pheno, but unlike what I have read of phenobarb (I've never personally tried phenobarbital) it was pretty euphoric, very wobbly, warm sort of high, that would turn your bones to jelly, and too much, would turn your head to mush for a while
Ended up getting dependent on it for a time. And then got wrongfully arrested and remanded, not on drug charges, but after I OD'ed and the paramedics fucking snitched me up for possession.
The DTs from barbs, going from my experience with barbital, were absolutely fucking horrific!, lasted months, almost completely delirious. When I finally came out of that state I'd gone without food for so long I looked like a jew that had just been sprung from a nazi concentration camp during the end of the holocaust having lost that much weight.
But with careful, responsible use, its the second-most euphoric sedative/hypnotic I've ever had, the first being chlormethiazole, a vitamin B1 derivative that whilst not a barb, is an agonist at the barbiturate/picrotoxin binding site on GABAa receptors.
I'm somewhat surprised that chlormethiazole is still around and in use. My doc didn't have any problem putting me on it to control my problem with myoclonus. Ugly looking chemical structure (namely containing a terminal alkyl halide), stinks to high heaven, and melts through many plastics (it has to be dispensed in glass bottles for that reason; on one of the few times I got it in a plastic bottle, because the pharmacy I used to get it from before they apparently became unable to obtain it, telling me it had been discontinued altogether...which it hadn't, were being sniffy and up themselves about sparing me the glass bottles week after week. Then after a week or so of storage, the plastic bottle of capsules had become clouded, and actually welded shut, presumably from traces of the volatile chlormethiazole freebase in the caps

))
I find chlormethiazole to be VERY similar to barbs. Whilst I haven't ever had any of the shorter acting barbiturates, only barbital itself, the very first of them IIRC, chlormethiazole is what I can only imagine to be pretty damn close to the mark in terms of subjective effects.
A litle off topic-I really do wonder why chlormethiazole hasn't been either dropped from use (almost) totally, like the barbs were, it shares so many similarities; being highly abusable, having a very steep dose response curve etc. as well as having a specific interaction with alcohol above and beyond ordinary potentiation. I forget which way around, but one significantly increases the half life of the other. I think, although I don't remember for sure, that EtOH taken with chlormethiazole makes the latter stick around for quite a lot longer.
Glad it hasn't though,as it controls my myoclonus very well indeed