Absolutely horrible. Being even "tipsy" (say, 8 beers or a bottle of wine) makes me notice it and be clearly sluggish the next day. Heavy drinking leads to tremors, nausea, a pounding headache, depression, and all-around weakness in the body for two days.
I usually try to avoid them, as in terms of short-term acute intensity I find them the worst after-effect from any drug (worse than heroin, cocaine or benzo withdrawals, except much shorter in duration). Cannabis helps with nausea, headaches, and makes me hungry, which is usually difficult while hungover, yet absolutely fundamental for recovery. If benzos are at hand I will always also take one. All but the most severe hangovers are cured with some dank bud and a couple of benzos. You're still couchlocked and useless for the whole day, but at least you don't feel like death.