I have just in the past 2 weeks traded my 2014 Suzuki VStrom 1000 for the KTM 1090 Adventure R. I rode the VStrom from new for 3.5 years clocking up just under 11,000 miles, all on asphalt.
Although I have only done 600 miles on the 1090R so far, I think I'm in a good position to offer some comparisons.
The main difference for me is the way the KTM delivers it's power, mainly from higher revs compared to the VStrom. Between 3.5 and 4K revs saw the VStrom at its happiest, it would sit planted on the road and munch up those miles. The KTM will do the same but at a higher more urgent revving engine, nothing wrong with that, its just the way the bike is designed.
The VStrom was very reliable apart from one instance when it went into limp mode during a trip to Scotland in a torrential down pour. This was quickly rectified by switching off the engine and starting it up again, fault gone.
On build quality, the KTM wins hands down. Better styling, better plastics and metal parts all round. As for reliability, my only comparison is my friend who owns a 2014 KTM 1190 R with 15K on the clock, he has had no issues what so ever in the rain, snow or heat, it just keeps going so hopefully so will the 1090R
The VStrom was much heavier than the KTM which was instantly recognizable. The KTM will flick around corners and tight spots easier than the VStrom which suits me being, shall we say, a mature rider.
On long runs, I did almost 300 miles on my first run out on the KTM and didn't feel much difference to the VStrom. The KTM sits nicely on the road and does exactly what you want it to. I changed the tyres to full on road going ones as I will never take the bike seriously off road and I couldn't see the need of running knobbly tires on asphalt, waste of time and the vibes would have done my head in. Speaking of vibes, the KTM is MUCH smoother than the VStrom, after 100 miles or so my throttle hand was numb riding the VStrom but nothing with the KTM, must just be better balanced.
To sum up, the VStrom was a great bike and loved it but the KTM has me hooked, if you fancy touring it will do it, if you want to be a hooligan it'll do that as well or if you want to go off road, well I think you know the answer to that one.
Happy hunting, Walton18