Just to share my experiences-
I had my wee one about a year ago. I came to hospital at 5cm and went straight in the pool. It was a great experience but definitely had cons. Unfortunately she didn't progress so I ended up having to go for an epidural (an awful experience for me!) but here's the pros and cons I found of the water:
On the plus side it is very relaxing, you can float around and all the midwives I had were really calm and relaxed while I was in the pool.
Quite a few negatives-it was really hard to get comfy for me. Don't know if it was the way she was lying but I couldn't lean backwards easily so was perched on my knees, they had towels underneath my knees but I still got pins and needles a lot. I got in and out of the pool once or twice for the toilet and definitely felt the contractions stronger and more frequently when out of the water. So in one sense I think the water is soothing but I personally felt it slowed my contractions. I'm not sure if she wouldn't have progressed anyway had I not been in the water. Thirdly the pool does get really manky haha. I poo'd a lot while pushing (lovely, lovely midwife discreetly cleaning it up-I owe her so much!!) and I really don't like the idea of that all floating around me. They can only fish out so much! A doctor friend of mine questioned the safety of baby's first mouthful of fluid being gungy bath water...fair point I suppose!
Have recently found out I'm expecting baby 2 and am debating now if I'd go for the pool again. I'm swaying more towards yes, despite the cons. Really hoping I dont end up back in the position of needing an epidural. It didn't work well for me, gave me awful reflux due to the position I had to remain in and I ended up vomiting everywhere.
Guess the bottom line is that you need to weigh up everything and make up your own mind
I'm certainly keen to hear other people's opinions-especially the negative ones!!