Personally I experience a lot of reflux from a variety of foods/beverages but I have never noticed anything bad from darker beers. My list of hangover brews (severe headaches) includes Stella, Champagne and Cider and I suspect this has to do with the yeasts used in these more than anything else. I'm also steering clear of Little Creatures, Fat Yak and similar bright ales again because I think the yeasts used create a combination of alcohol and other bi-products that don't like me.
Something I remember reading/seeing/being told regarding the effects of alcohol is that the amount of sugar has a bearing on the effects. Specifically, things like Rum and bourbon that are higher in sugar tend to make people more violent than other distilled drinks like vodka for example. I can't cite any references but again personal experience seems to back up this hypothesis.
"I woke up with a bad hangover this morning after about 12 bottles of HB. Would the problem be with my mash temp" ?
This was in my first few AG brews and I was mashing at about 63 - 64c. It turns out that the beer might have been a bit more forgiving if I had mashed at a higher temp, it would have had less fermentables and not been as dry.
But obviously having 12 bottles was a hangover setup regardless what I was drinking...