I don't know how radiation effects things, but I just had my reversal on Tuesday and wouldn't say my experience has been bad at all. Yesterday was rough because when my bowels started working they were on overdrive and I ended up going 14 times in 24 hours (2.5 liters day shift and a 1.3 for evening shift). I was super dehydrated and felt wiped out. They cranked up the IV support and by morning I was feeling much better.
So far today (I've been up for seven hours) I've been to the bathroom twice and feel pretty good. Even yesterday when I went so many times, I was able to hold it until I got there and had no accidents. I've had a little gas pain, but walking (especially after meals) seems to helps with that.
I'm still new to process, but so far satisfied with my outcome. I hope that helps!