I've done both - and thrown up both. But for some reason, for me, it takes a long time after drinking these preps before anything actually comes out. Having it all sit in my stomach for so long tends to make it just come right back up after awhile.
The only one I can do without throwing up is the Miralax/Gatorade prep. That one still sits in my stomach, and I look like I'm pregnant for a few hours, but since it doesn't taste bad it doesn't cause the gag reflex for me. I have my colonoscopy this summer and I'll for sure be requesting this prep.
I used to love that phososoda prep, I think I've had that one twice before they took it off the market for causing kidney issues. That one was such little volume, I used to just drink it fast then chase it with ginger ale. Of course ginger ale makes me burp like mad so I can't have that with the larger volume preps - just more fuel for throwing it all back up!
UC - diagnosed 1994, in remission for 10 years, currently trying to get over a flare
Meds: Prednisone 12.5mg; Colazal 3 pills/3x day, 1 mesalamine enema a day, VSL #3 DS 1/2 packet/day, Align probiotic, Ultimate Flora 30 billion, iron, calcium, folic acid, L-lysine, Zyrtec, Yasmin, multi-vitamin, evening primrose oil, zinc
Tried Imuran but it affected my pancrea