I have had mine for 25 years. Life or Death choice, so, I can't really regret. But, it gets to me sometimes knowing I really should not be here. But, maybe that is just me. Pain, hurts like hell, but a few weeks after you'll be fine. You certainly won't miss the pain of having diarrhea all the time, that for sure. I healed fine from first surgery. Second surgury, when the completely removed the rectum, I got an infection in the sutures on my stomach. Not good. Also, the healing time for the rectum was long. Lots of packing and waiting for it to finally heal up. And if you don't pack it well you can get pockets of infection and you have to start over from that point.
As far as getting use to the illiostomy. It is a learning curve. You'll have spillage, your bag will fall off, you won't always get the pad just right. Like previously stated, you'll learn you need to wear different clothing, watch how you sleep, don't lean on, etc. I think the thing I miss the most is sleeping on my stomach. Don't feel bad if you have an incident, I still have them from time to time, especially when I am feel well and can be active. Sometimes I will just bend the wrong way and next thing I know it is leaking out the side of the pad.
But, not having that nasty old colon trying to kill me anymore makes all the work worth the effort. Beside, my cousin is a paraplegic, so it is all relitive. Life is what you make it.
You will be fine.
Peace and love.