Met both and while they seem interchangeable because the effects overlap and usage is kinda the same. The addiction to both substances is different as are there reinforcing behaviours. Just as the effects are different enough to agree they are nothing alike. But for an outsider the addiction to both substances could appear alike.
GHB/ GBL are very high floating intoxitants which are way more easy to overdue. They will feel good. even when your at the porcelain god doing your offerings. Very little regret in doing it again.
Ethanol feels very bodily and heavy, slower for better words, more intoxicated. And comes with a hangover even during usage u will feel it coming! You will try to avoid to make any offerings. And the after effects are that brutal, would be it a illegal drug. It be enough to prevent you from using it again any time sooner then when you kinda forgot about them. But the availability, legality and acceptance favor it imo at this time. And the exhaled fumes issue limit it's use.
Normal usage to GHB/ GBL would have minimal after effects.
But overdoing it as the G wears off after to many doses, your awakened feeling anxious and stressy. The dopamin rebound was dismissed, but it certainly feels like a rebound effect of something. And in that aspect it resembles a very very high alcohol intake, which has a sudden awakening effect akin to G rebound.