Someone told me that if I was interested in one not to test drive it as that might put me off, get one and you will soon get used to it. I test rode two 1200GS's and then bought a F800GS never regretted it. But I'm not going intercontinental or global, about 6000 miles a year mainly in Wiltshire/Hampshire and only on the roads.
On the other hand they can't be all bad, just look how many there are on the road and the dealers show rooms are full of them as they keep selling.
By contrast I did the complete opposite. Bought the F8 but there was something lacking in it for me , maybe it was the effortless torque and the feeling that I had to keep it buzzing - the bike just wouldn't let me ride it slowly! I took a test drive on two 12's.
The F8 has the far better gearbox of the two but that just wasn't enough for me to prefer it over the 12.
I chopped it in for the 12GS and what a good move it was , no regrets whatsoever.
Go for it!