I had both
I sold my '04 1150GS after purchasing my F800GS. I really loved the 1150GS and took it on some great trips. On one of the trips we took a 200 mile dirt road excursion through Utah where I found that I wished I were on a bike that was "dirtier". (We were completely loaded up with camping gear, and supplies for a couple of week on the road)
Now that I own the F8GS and have put a couple of thousand miles on it I am very pleased. While I would not describe it as a "dirt bike", it is a outstanding dual sport bike. Blasting down the road at 80 MPH or moderate trail riding at slow speed is not a problem. Bottom line, for me and my riding style, I love this bike.
I have installed the following stuff:
GIT skidplate and engine guards
Barkbuster hand guards
Cal Scientific windshield (large)
Jessie safari saddle bags and large top box (with quick release)
I am waiting on the following:
Comm system (StarCom digital)
Sargent seat (I'm on the list)
Alaska, late June '09 from LOUISIANA
(that would be from the Gulf Of Mexico to Prudeau Bay)
Wringing the most out of life above and below sea level.
"09 KLR 650
'08 Harley Davidson CVO Ultra Classic