I'Ve had a pair a little over a year now (put A little less than a season in Them).
If you like the KR2's you can't really go wrong with the Lupos. They are essentially the same boots, just the added walkmode and the rubber sole.
As for the Walk-buckle I am yet to have any issues. Super burly and gives you A Nice ammount of leverage. The boot is however quite Heavy vs. More touring-specific boots, so you won't want to use these on the longest tours unless you have legs of massive steel. They are definetely A downhill oriented boot, and excells in that direction While remaining functional for shorter skins and slackcountry tours.
I've found that the rubber sole isn't quite as durabel as the solid PU/plastic sole on the KR's, however they take A good ammount of rock and asphalt till worn Down (i am yet to replace mine).
So, if you plan on shorter tours, this is in my opinion A Big step up over the KRs, While still remaining the characteristca of the KRs though. Both boots are great, and if you fit the KRs it should be no worries coming into the Lupos - it's just A matter of preference and intended purpose between the two really.
Hope this can help A little.