I asked for advice about this a few weeks ago and took the plunge and ordered one, just thought I'd come back on here and share my views.
BRILLIANT!!!!!!!!!!!!!!!!!
Today was the first chance we got to use it as I've been quite ill. DD1 (4 years old so at the older end of the scale for the Rothan) can be a bot of a wimp at trying new things and she really wasn;t keen on going to the park on her bike earlier, but DH tried some reverse phsycology on her (told he we were taking the bike but that she couldn't ride it he was going to carry it - no I want to ride it she screamed - oh OK then!) and she absolutely loved it.
Now I did read somewhere that it only takes some children 20mins to get the whole balance thing but I didn't really believe that, but it was true, she loved it and wants to go on it every day (thank God - not the most expensive bike aroubd but not the cheapest either).
She rode it all the way to the shops and back without complaining. Was very light when DH had to carry it (safety reasons, not cos she was bored). And she was so proud of herself.
So for anyone considering getting one - go for it.
And no I'm not employed by them or on commission!