When they came out they were better in several respects... They looked slightly more modern, the FI was smoother as an updated version and the had 6 gears, often with the extended 6th... As time's gone on and I've kept returning to the 11 I think....
The 11 look has aged better and TBH the clocks setup was always better...

The FI... Well the 1150s smoother but you can live fine with a well set up 11 and it's only slow speed running where you notice the most...
The high 6th was a passing phase... If you've had it for a while you'll change gear more on the 1150 and the jump down from OD 6th to 5th is a PIA .. Also with 5 from 50mph on you're always ready to go and still plenty of engine breaking...
I was a bike instructor at the time and had an 1150 demo out and wanted one but now I'm not bothered...
Lastly the suspension setup in more compliant...
1100s were the bike BMW built you and 1150s were the bike they thought you'd like to try and get buyers to crossover to them... Really the 11s were the last bikes built without that wish to cuddle the customer...