Hi 
Funnily enough, my sports horse is descended from Mill Reef!
I have an ex-racehorse. I used to look after and ride him while he was in training, then the owners kindly retired him to me on long term (forever) loan.
He is very sweet, genuine, lovely attitude to work, not very bright (but then my mare has enough brains for the both of them!
) and a joy to own really.
He retired from flat racing aged 6 (in the october) and came straight to us. He spent about 10days roughing off, then we turned him out (still rugged up to the eyeballs) in a field with a field shelter and lots of others in next field. He was there for about 2 months, then we moved a pony in with him. He had around 5months holiday.
We brought him in, started long reining (not a success) lunging and then took him for short hacks with one other horse for company. Unfortunately i was involved in an accident and so he had to be turned away again for another 6m.
When we got him he was a terrible mover, but we only wanted a horse for DH to be able to hack out, so it didn't matter to us how he moved.
He now moves beautifully! He was just very jarred up and having the best part of a year off was the best thing for him. We have done a bit of dressage, a mini hunter trial, some showjumping and hacking with him and are hoping to do some ex-racehorse show classes this year.
The main things that needed work in the early days were his diet - he would never really eat hay, now he has a very high fibre diet. Getting him used to being tied up outside, and getting on him. You forget they have never seen a mounting block before! He now stands still while you mount, and is happy to stay standing while you faff about doing stirrups etc.
There is another ex-racehorse at our yard, and both him and ours tend to get very attached to their fieldmates and hate being left in/out without them.
I hope this helps at all 