IMHO the 990 and the Tiger are too close to the same thing. very close in weight if you compare magazine numbers, and similar. I have a buddy that just got one and I seriously considered the Tiger XC, F800GS but ended up buying an older Super Enduro (they stopped making them in 2009) so I wanted something more off road capable.
I guess since you have the XC, I'd consider the 950 Super Enduro if you plan to do a decent amount of street but want more capabilities off road, or maybe a 690 if you ride solo a lot, and not quite as much street (easier to pick up solo), or even a 500 EXC if you just want an off road bike that is street legal.
I have a 450XC that's tagged but have been having so much fun with my 950 off road that I don't ride it nearly as much as I used to. Not going to sell it or anything but i have been enjoying my 950 SE a lot. I have friends with the ADV's and they ride them well off road, but there's just something about the SE that makes it more fun to ride it faster/harder off road. Maybe it's just more crash worthy than the bigger bikes. :)
just my $.02