I've owned a DL650K9 (or something like that - the original shape anyway), the second gen 650, a 2014 DL1000, and have just bought a DL1050XT.
The second generation 650 was definitely a step up in refinement - all the rough edges of the previous model had been filed off and it was like riding an armchair. Very comfortable and easy to ride. However, I wanted a bit more power and for it to be a bit more "planted" on the motorway, so I bought a DL1000 in 2014. I *thought* I was getting a quicker more planted armchair, but it was nothing like the 650. Yes, planted, but heavy, with much of that weight up high, which made it hard work for tiny back lanes and awkward manoeuvres (tight T-junctions on steep hills sort of thing). And low down it was indeed punchy, but unrefined, which made town and low speed also hard work, with plenty of clutch slipping to prevent Massey Fergusoning myself into the car in front etc. In short, low down grunty, planted, hard work at slower speeds. Seven years on I decided to get a 1050XT.
The 1050XT doesn't feel like a big adventure bike. The engine is much more refined, with three engine modes, all of which are smoother than the 1000 (which does feel very agricultural when you get back on it) though none of the modes offer that same low down punch. It's feels a little less "planted" on the motorway than the 1000 too, probably on a par with the 650 I had. But the slow speed stuff is a joy - effortless, almost like riding, er, an armchair. Oh. This seems to be the bike I thought I was getting (and hoped I was getting) when I sold the second gen 650. The higher speed stuff is more fun and less effort too, once you accept there's no big shove from the off. It is definitely more sporty in its handling and engine characteristics, which is actually quite nice. "Flying" round a corner and spot a drain cover you need to avoid? No problem, just change line slightly. On the old DL1000 that was usually more physical effort than it was worth, so I just thundered over the drain cover! Part of this lightness is down to different size tyres, of course.
The dash is too busy and some of the UI seems wrong - I'd much rather have a larger clock font, as I look at that more often than the TC mode I'm in, for example, but instead someone decided that the font for the TC, engine and ABS modes should be twice the size of the outside temperature and the current time. But it shows all the useful stuff and changing things is pretty intuitive. (There were mutterings that it scratched easily, so I splashed out a tenner on a couple of screen protectors. Jeez, what is the world coming to - screen protectors for a motorbike?!) The worst thing about the new bike is not the relative loss of character (I think it'll develop its own character once I've stopped comparing everthing to the DL1000) but the extraordinarily uncomfortable seat. I think there must have been a shortage of seat stuffing in Japan in the last 2 years, or Suzuki are cutting costs even more, because it's (a) very narrow and (b) very hard without much padding. It's probably fixable in some way, but for now it remains a metaphorical and literal pain in the arse.
I've not had the 1050 long enough to draw any conclusions (apart from about the seat) but I think on balance I prefer it to the DL1000. The coming months will tell. At the moment, I think the bottom line is if you do a lot of town and/or tiny back lane riding, and/or you like a sportier response, then this is better than the 1000. If on the other hand you spend most of your time on big sweeping A roads or motorways, then the 1000 is probably a better bet.
(Oh, and I asked the dealer to swap the spoked wheels for cast before I bought it, too ;-))
