well, it has been nearly a week now (I think - time scales are a little blurred here due to lack of sleep), and I can't really see any adverse affects.
she doesn't like drinking it (but will have a few sips), but accepts it ok on her cereal. teeth issues were one of my main reasons to try the change over, especially since she will only drink fruit juice too (now watered down, at least)
dd1 does have circles under her eyes, but I'm not sure this is down to the milk (they were there before the switch too, and are related ot general digestion as after she has had apoo they are lighter, so need more investigation) she has recently started eating apples and bananas again, and think this might be the cause
her behavior is definitely not any worse - she has, in fact taken a few steps forward, eg last week I was strapping the dds into the car, and after doing dd2's straps, forgot to give her her smelly rag favoured teddy. as I walked around to do up dd1's straps, I said (not too hopefully, but justin the spirit of normality) "dd1, could you give dd2 her teddy? we don't want her to start shouting for it", and by the time I'd got to dd1's door, she was handing teddy over to dd2 with a concerned "say thankyou dd1". I was
she has also learned to ride a scooter (albeit slowly - need to get her one without 2 back wheels, as she gets her feet caught up a lot)
but yes, dietary issues are a nightmare. we have also stoppped dd1 havign lunch at school recently, as they were not taking food issues seriously, imo.