I also advocate the trying on before buying option. I tried 12000yen Shimano and then a 20,000 yen pair of Sidi's, the guy in the shop said the Sidi's were much better especially if i got the special 5000 yen sole linings, but I thought the wide sized shimano was way more comfortable.

I ended up buying a 43, even though I usually wear a 27cm shoe (44 in Euro speak).

You never can tell with foot wear.

Although I am glad I spent the extra for the pair with a rachet style strap as it is nice to flick the tension up a notch every now and then. Or even losen them off easily when you need to.