Having owned both 1150 and 1200, I would say that preference would be a personal thing given that the bikes are so different as to be difficult to directly compare.
My preference is for the 1150 ( I sold the 1200 and will now buy an 1150 Adventure before they disappear) for the following reasons in no particular order;
1) Looks and street presence. 1150 built like a rock whilst 1200 built to save weight - Tank side panels feel like cheap plastic and don't fit perfectly, pannier mounts drop off, panniers flap in breeze, top box mount takes four times as long to instal and cheap fasteners easy to thread, etc etc)
2) Power delivery - one report shows that 1200 makes half as much torque below 3000rpm and you really feel it.
3) Engine feel - balancer shaft replaces thudding pulses of 1150 with tingling vibes which I found particularly annoying because the narrower diameter handlebar grips are less well padded.
4) Seating position - 1150 more in the bike, 1200 more on top of it.
5) Clocks - I liked the added features of the 1200 but the 1150 clocks are far clearer and the fuel gauge actually gives you a clue how much petrol is in the tank !
In summary, if you would buy a Range Rover, go for the 1100. If you would buy a BMW X5, go for the 1200.