sorry - this is long, if you can't be bothered with details, water births are good!
first birth I'd planned a home water birth and ended up transferring to hospital (meconium in waters) had dd1 on a bed there. I did tear quite badly, it was recommended that I needed stitches but I refused them, Just being examined was very painful and my lovely midwife (who I'd know all through pregnancy and had been at home with and who came with us to hospital) told me I'd probably heal just as well without them. I was sore afterwards, very uncofortable for a day or so, then sore for a bit longer but healed fine
second birth, dd2 was the best of the lot! home water birth in middle of night, very calm and lovely. I didn't really push her out, breathed lots and it was about as relaxed as it could be. I had a very small graze and felt fantastic afterwards.
third birth, less relaxed home water birth due to some issues getting hold of trained midwives when I was in labour. All was OK in the end, but only got the right MWs there 2 hours before dd3 arrived. I had a very small tear, all Ok afterwards.
fourth birth, again bit stressful due to lack of qualified staff. In the end the MWs who attended in early labour weren't qualified in water birth, they left as things weren't that far gone. Things then got going very fast and they missed the birth by 5 minutes! just as well really as they'd have tried to get me out of the water! no tearing that time at all
For both the third and fourth births I had explosive deliveries- there was no second stage as such, the baby just burst out with a contraction. In my notes for #3 the second stages is recorded as 1 minute, but the midwife told me that's cos it has to be a time for the computer records, it took much less than that.
So yes, tearing was much less in water, but I'm not sure that's becuase of the water, or just cos everything's strecthed already! the water births were all easier than the first one, had loads of gas and air in hosptial but only tens the pool at home.