Firstly, I'm so sorry that you are reading this and considering what option is best for you. It's not a pleasant experience, physically or emotionally.
I have experienced 2 miscarriages in a row, both around 9 weeks and both requiring further procedures due to retained tissue. So I'm going to talk you through my thoughts and experiences of each one:
Medical Management - the first option I tried, this felt the best for me as there was no surgical procedure, it could be done in the comfort of my own home etc. From taking the pills, I was in pain for around 6-7 hours before I went to bed. They recommend doing it in the day incase any issues arise and you need to go in to hospital. I did it about 3pm on a Friday, which meant I could sleep the last of the pain off. It was painful, but nothing I couldn't handle, however I couldn't get off the toilet and sat there for hours. I did throw up once but I think that was from the codine. All in all, unpleasant but completely manageable. However, important to note, unfortunately it didn't work for me and I still had retained product, which leads to me on my next option...
MVA (manual vacuum aspiration) - not all hospitals offer this as an option, but mine did. I had no idea what to expect and was very scared beforehand. They give you medication to soften your cervix and send you away for a few hours. When you come back, you are put in your gown and taken into a small surgical room within the EPU, which is great and quite a comfortable place to be which you are probably already familiar with. You can have someone in with you the entire time to hold your hand, which is also fantastic. You are given gas and air, which was a god send. They then put 4 injections into your cervix, the first one is horrible but you can hardly feel the other 3. They then go in and vacuum out any retained product, this is very intense pressure, which does hurt, but they will give you breaks and stop if you need them to. It takes about 10-15 minutes and it's over. Once it finished, I felt very lightheaded, felt sick, was shaking and felt like I needed the toilet (even though I didnt). I felt like I couldn't close my legs and hobbled off to my bed. You then sit for an hour or so with a cup of tea and a biscuit, and your off home. This is a fantastic option if you are a busy person, have other kids you need to get back to etc. However for me it was the worst, quite traumatic and painful.
D&C under general anaesthetic - long day but if you have the time, it's a great option. I was given my own private room with TV and bathroom, which was lovely.
My biggest fear was going under anaesthetic as I had never done it before, but it was just a needle in your hand and that's the worst of it. I don't remember falling asleep, woke up and it was all done. Went in at 12 noon, didn't get surgery until 3:30pm, back in my room by 5pm and home by 6:30pm. No pain whatsoever even the days following.
It is higher risk of causing internal damage, but risks are still very low.
Happy to answer any additional questions on any options, but just remember, these procedures are all common, once it's done, you will be able to move on, and you will be fine.