F650GS
I happen to own both the 1150GS Adv and a 650 Dakar, so I am able to make a reasonable comparison. Recently, I purchased a KTM trail bike and thought that I should sell the Dakar, just to keep her-in-doors happy, as she thought three bikes is a bit too much.
The following is a true personal opinion of the F650GS Dakar.
I have owned my Dakar bike for the last three years from new. I first wanted one, after a two day off-road skills training course with the late John Deacon in Wales. I had ridden off-road before, but only with low powered small c.c. motorcycles and I was amazed at what these bikes could do if you knew how to handle them. So I highly recommend the off-road skills course, as most of the skills that you will learn can be directly related to riding these bikes on-road. If you do intend to ride the bike off-road, let me also say that this is no "mud plugger" and will get bogged down if the going gets very heavy. This bike is a large lump to pick up again on your own, but again, if you have been shown how to pick it up, you will be able too. You just have to be fit, if you have to do it several times an hour!
I had a few teething problems to begin with when I first got the bike, in that after a run of a few miles when coming to a halt at traffic lights for instance, the engine would just cut out. On one particular occasion the bike just would not start again, leaving me stranded miles from home. Fortunately, the BMW rescue service took me home and the bike was taken to my dealer. I gather that this was a problem with some early models and the fix was to re-map the ECU with a software upgrade, and the problem has never reoccurred. I cannot fault the build quality of the bike, after more than three years there is no rust to be seen, and apart from servicing, tyres etc; no mechanical parts have had to be replaced, apart from chain/sprockets and swing arm bearings. All the rest is still the original, even though the bike regularly gets a thrashing off-road. Now just over 12,000 miles later I cannot fault it.
You have to be fairly tall to reach the ground with both feet, but lowering kits and a low seat are available. Last year I rode the bike across France to the Pyrenees on a BMW organised trip, all the other blokes on the tour were on R1150GS or K1200 bikes, and I guess that when I turned up at the ferry they must have thought that they would have to slow down to enable me to keep up. However, the reverse was true, the comment that I heard later was that I almost rode the wheels off the thing. There is no doubt that on a straight road, sport bikes will thrash the bike, but on narrow bumpy "B" roads, the bike will soak up the bumps and leave sport bikes in the dust, heh, heh! I can literally throw it round bends, even with knobbly tyres on, as it is very predictable. In traffic, it's a dream to just sail past all the drivers in their cars. You are very much in command with the high up view of the road ahead, and can easily see over car roofs and hedges.
There is only one minor complaint that I have, and that is the front brake can sometimes be overwhelmed at road speeds, with the weight of the bike. But then, I'm comparing it with the hugely powerful brakes on my R1150GS Adventure and the K1200RS that I used to own, and it does take longer to stop than these two bikes.
Since new, I have installed a Remus exhaust system, a K&N air filter, almost every Touratech part imaginable apart from the full Dakar race kit. It now gives better mid range power and is very easy to wheelie, woohoo!
So I'm still VERY reluctant to sell it. It's advertised in the For Sale section, but I'm not too bothered if nobody buys it.
Place an ad virtually Anywhere WI, National Care Homes for the Insane and you get your Arm Torn Off by the Hordes wanting to do that very Deal 
