Re: Hard Floor
I have to second Daren's opinion here.
You are as likely to need breakfalls in a fight as you are bowing skills. They are just a part of practise that allow us to continue training, an artificial element that is essential for repeated practise of techniques. Making uke fall is a by-product of techique, not the aim of it.
Regluar training on a hard surface will not add anything apart from increasing the risk of injury and forcing techniques to become less dynamic.
The only benefit I can think of by taking an occassional fall on a harder surface is that it may help you realise where your falls can be smoother. However, regular long-term training will iron out problems like this, and you're less likely to injure yourself along the way.
Ian (who admits to falling onto concrete recently ...accidentally I might add)