I did that in June last year.
At first I thought I had made a mistake, but now I'm loving it. I came from a 2016 1190R which already had a lot of good updates over the previous 1190s: The stronger Akront rims, different rear suspension setup to avoid bottoming, better starter and various heat shields to save the balls. So it wasn't a big jump for me, but from an earlier 1190 it will be a big improvement.
I feel like the 1290 is better though. It gives up nothing offroad, and I seem to be riding much faster now than I was o the 1190, with little effort. It rewards precision more. I found I could chuck the 1190 around and it would work. I can do that with the 1290, but if youactually concentrate and do things properly the suspension lets you know you're riding properly and it's smooth as anything.
It does feel like the front end is a little heavier than the 1190 was to me. But shifting your weight a little back makes that disappear totally.
Get the quick shifter. I wouldn't bother with the full travel pack though. It already has a mechanical slipper clutch (so I don't see the need for ASR or whatever) and the Hill Hold assist just annoyed me on test ride.
You might feel that it's handling is quite a bit sharper on tar, turn in is quicker etc, but that it's a bit more nervous at speed. I felt that but am either completely used to it or the bike has settled down with some mileage.
I think it's just as good, of not a bit better offroad (due to suspension) and quite a lot better on tar. The electronics are really nice.