Better to Have?

Pro diarrhea:

<I like pooping better, cuz to me, all I have to do is sit and do nothing. Whereas with purging, it takes a lot, you gotta have buckets and stuff, you gotta deal with THT constant "gag", you gotta taste it, you gotta let the barf burn your throat (stomach acid, man)>
<Not to mention sticking your face in a toilet instead of your butt.>

<And take this analogy:>

<When I barf, I feel sick all over. When I leak poop, only my butt is sick.
And that "feeling of needing to spray the toilet with poop" is prettymuch the same feeling as needing to fart really badly>

<So if you ask me, I would rather sit and do nothing at all on the pot while leaking a poo than to shove my face in the stinky pot, eat my own poop, set fire to my throat, having to watch the mess come out right in front of my face, choking on my own excretement, having to deal with those occasional "oh I'm about to barf again" but it only being a false alarm, not to mention the smell of the crap (coming out right under ye nose) and especially the persistent nausea.>

<Not to mention you can't let out barf just anywhere, there's not always something it can go in if it comes up by surprise. Whereas with the poop, man that's what pants are for :P sure, it's nasty having to sit in it all day, and smelling like rotten poop, but people won't have proof that it's you>

Rebuttal (pro vomit):

"All you have to do is nothing". When you poop, even if it's pure liquid, you still have to use muscles to open your anus. And, unless you want poop stuck to your butt, you need to consciously keep it open.

"Sticking your face into a stinky toilet instead of your butt". You can smell your poop just like you can smell vomit. Bottom line, it'll smell bad either way.

"Barf burns your throat". True it does. But poop burns you butt after a while. And having to wipe after every leak will cause the anal tissue to become sensitive and burn. If you don't wipe after literally every leak, the poop germs on the skin will burn. Also, the repeated wiping can eventually cause hemorrhoids (which are a whole other problem and annoyance. 

"Can't vomit into something 24/7, but there's always pants". You can vomit anywhere and just clean it up after. If it's outside try to find where people won't step in it. Once you've vomited, it's done and you're done with it. If you leak into you pants, you can't necessarily change right away. The resulting germs against your skin could cause an infection. For instance, urinary track infection.

Nausea is a bother to deal with, but holding in poop is also no picnic.

Also, true that false alarms of throw up can occur, but if you have severe diarrhea, the need to fart is also a false alarm. You have no way of knowing if it'll be gas or feces.

Another reason why vomit is better to have:
If you're a girl on her period, diarrhea causes another whole slew of problems with changing tampons and such. With vomit, gender is irrelevant to the side effects.