I usually play DF high. Actually, I spend 80% of my leisure moments high, and I only play DF on my free time (and I have little) so, yeah.
Of course, weed is MUCH LESS hazardous than alcohol in every way, and it's effects aren't even near as being drunk. It makes you extremely absent-minded for everything except what you're focusing. In counterpart, it makes whatever you're focusing extremely more "wide", after a while you'll have your mind wondering (and wandering) about things, and then wondering about what you were just wondering, eventually making you forget what you were first wondering.
It also makes you more imaginative and focused so it is common that I spend 1 or 2 hours trying to do something random and sometimes even stopping it on the middle and starting something else.
It makes you more creative too. It makes your mind behave a lot differently, it is hard to explain if you never experienced it at least twice or thrice.
And actually, my results are fairly decent. I tried to play DF a while ago (1 year I think) and I couldn't even begin understanding what all those letters were and even when playing with a tileset it would be a little tough for me to understand some things. Most of the mechanics were too much for me to bear.
I had just tried a tutorial with everything preset and it wasn't that good IMO. It used a "user-friendly" language which made it pretty harder to understand. I think it was a well-known guide on the 40d, didn't help me much.
I started what can be considered my very first fortress a few days ago. I only played it a few hours (will probably play more today and weekend) after reading some stories (I think everyone's been there) and dude, Boatmurdered was an AWESOME HIGH READING. Reading while high is one of the best things ever (listening to music, everything that makes some parts of your brain "tick" that aren't frequently ticked, so it is like a completely new feeling) and I've spent a few hours reading my very world's Legends. Before I embarked, I forgot a few times to play and kept reading Legends for hours, just because you begin to wonder about stuff and imagine the world like it was real, it makes you really 10x or more creative.
But for me, playing DF high is both an addition (it makes pretty much everything non-serious better, and DF is awesome enough so awesome + awesome = yougetit) and an addiction, on the other hand I consider alcohol to be one of humankind's biggest scourges. I dislike it's effects almost completely (I like being tipsy because it helps with timidity and all) and well, it is one of the cruel killing machines out there. It is not even organic FFS and it destroys lives. Lots of them.
Yeah I had my drunken days, I don't have anything against people doing alcohol I just wouldn't do it myself anymore, it is the heaviest drug out there (yes, way heavier than cocaine, believe me. A little heavier than heroin because it's legalized) and I think it could lead to !!FUN!! stuff. But it basically makes you disabled, so it is like playing DF handicapped, whilst playing it high is pure awesomeness.