I've owned the older (carbed) F650 and currently have a DL650.
The FI F650's weren't as good as the carbed versions - which is why I don't own a BMW - couldn't see the point of spending big $ to get a bike that was worse than the one I already had.
If you have any riding experience, the DL 650 is probably a better bike.
Where it falls behind: Worse turning circle. No engine protection.
Turning circle only experience can deal with - not a big deal for me, but I could see it getting a new rider into trouble, engine protection is fixable - or ignorable - if you are only doing light off road rides. Everywhere else the DL is pretty much a clear winner, far better on road, far easier to ride off road - provided you aren't racing - and as far as I can tell it's more reliable as well.
I'm not saying the BMW is a bad bike, just that the DL is just far better value for money and will do everything the F will.
In theory the Dakar looks to be a far better off road bike - I'm unconvinced - provided you aren't doing extreme things (Paris/Dakar
) the DL is a really easy bike to ride offroad and is much less effort than the BMW. I found that not being as tired muscling the bike round more than made up for any weaknesses the DL might have.