Those gravelys have a lot more power the the DBs but the DBs do have a brush cutter if you can find one and they work quite good for light brush up to about pinkie size or so not as good as a billygoat or DR but they can do an ok job
I don't know how the gravely brush cutter compares the DB brush cutter, but I have one.
here's a thread elsewhere with my gravely when I modified it for wide tires. It has the brush cutter on it in those photos. In heavy grass with the brush cutter is when I wish it had more power. It has so much rotating mass it will cut about anything for a second or two (saplings or whatever), but an ongoing load of heavy grass bogs it down.