I had a Tiger for just over a week. I hated it. It was very top heavy and it struggled to make progress, it felt sluggish and awkward. I took it offroad and to be fair it wasn't too bad, far better than i expected but on the road it was not for me. It was fairly comfortable but just didn't feel good, it gave me no confidence.
The big R-gs's feel fine after a few days. They are intimidating at first but you soon get used to the size. Even now, no bike looks big to me any more after owning one. I had the 1200 but the build quality lets it down, the older ones are reportedly far better. I've chatted to owners and the story goes you buy the 1200 and replace bearings, batter and shocks, the 1150 and do something else (I forget what) or the 1100 and just ride it. They're not for everyone.
I had the F800gs. now it's a nice bike but it's massively compromised by gremlins. It's a through and through Chelsea-tractor built to seperate you from your cash, not to do the job its advertised to do. I'm off soon on a big ride and one of our guys is using one but his list of failures is comprehensive. I had many of them on mine, my brothers failed and we had a second one which also failed. Also you have to work them hard to get to that hidden power. It was not a fun bike to ride hard but it was a fun bike.
I just got back from Europe. We did a month 2 up on a little rotax powered G650 with lots of luggage. I took a girl so there was a lot of luggage! I'm not going to lie to you, on motorways we managed 65 fine but I would have liked more power, we got to cruise as fast as 80mph when we were running late and made better times than that on occasions but she did feel breathless sometimes. I had to replace the shock and springs and otherwise the load would have been too much I think but the Dakar, for instance, is taller and might have coped even better.
In my experience, if you have a passenger then you need to wonder if you're going to do any offroad work at all. I felt I would have been better off on a purely road bike some of the time. Having said that, I met a guy on the road, he was on a Bandit 600. I got 80mpg on average, he got around 40 so that was a big difference which made up for those slower days... also on occasions where a bike did blast past us we invariably caught them up at the next petrol station, massaging their wrists and back. Different strokes, I guess.

Everyone has different experiences I guess ... I've just got back from a 15,000 mile eastern europe, Georgia, Armenia, etc trip on an F800GS. 70% good tar, 20% poor tar and 10% dirt, one-up.

The bike was faultless. Never missed a beat, superbly reliable, comfortable (with a sheepskin), powerful, fuel efficient, flexible on all roads, not overly heavy, no gremlins, no cash outlay beyond the cost of purchase. Sold the bike for the cost of purchase, and will definately buy again.

For parts of my trip I travelled with several other F800GSs, and not one had a problem.

The 2008/2009 models were subject to a few recalls (chain, fuel sender), which seem to have been ironed-out now.

To me it was the perfect bike for all roads - it cruises comfortably on highways and can take the dirt. In my opinion the bike does precisely what it's built for.