I own both a good pair of motocross boots as well as the strictly street-oriented leather boots I used for years before I started riding dirty. For the adventure rider who wants one boot to rule both types of riding, Falco has introduced the Avantour 2.
My two pairs of boots are completely different in nature. My street boots are comfortable and flexible while providing decent protection from the risk of road rash. My motocross boots, on the other hand, feel like a modern interpretation of medieval armor. They are extremely rigid, allowing only enough flex to operate the foot controls, and even then only after a full break-in period. They are not nearly as comfortable, but they're not bad, and the trade-off is far superior protection when your bike decides to take a dirt nap. They have certainly saved me from at least one broken ankle.
Das Boot:
The Avantour 2 splits the difference between these two types of boots. It provides some armor in essential places the same way a full-on motocross boot does. It uses 3DO-backed ankle cups, and earns a CE certification. It uses a similar buckle system as a motocross boot to keep your feet firmly locked inside, with anodized aluminum buckles that are fully adjustable and replaceable.
However, this boot is also much more comfortable and flexible than the hardcore dirt options. The Avantour 2 features leather construction and a waterproof membrane liner that will breathe better than a motocross boot. good for long days in the saddle as well as walking around exploring remote areas or your local bike night. The compromise is that its softer sole makes it more difficult to ride while standing on the pegs like you should on dirt.
All in all, the Avantour 2 is a great choice for the more road-oriented adventure rider who may also tackle fire roads, but not serious off-road challenges. For a serious dirt enthusiast, or for a total newbie who crashes a lot like me, I'd still recommend a full motocross boot, because your feet, ankles, and legs are precious. If you don't tackle trails, though, a dual-purpose adventure touring boot like the Avantour 2 would be the perfect compromise between protection and comfort, whatever the road surface happens to be.