Nicolas -
The 11 is MUCH bigger than the 10 in all respects - but especially in thickness off of the wrist. Here is a pic of it on the wrist - keep in mind that my wrist is above average size - about 7-3/4 inches.
Here is a shot of the thickness of the watch:
Finally, they really got the pushers right - even the crown is larger and nicer:
Rumor on the street is that prices are going up on all RMs, especially this model. So if you can lay your hands on one now, the timing may be right.
My understanding is that the reason the price difference is not that great between the Ti, RG and WG is that in the 11, the gold versions are not solid gold; because of the size of the watch it would have been much too heavy to make them all gold and hence they are just gold on the top and bottom pieces of the frame.
Its a great watch - in my opinion the dial is just alot more interesting than the 10 and the size, well, let's just say it dwarfs the 10 and has quite a presence !