ABS is a double edged sword.
Sometimes I feel it does a great job and makes something easier or it saves my bacon. At other times the awkward feedback in the levers raises my adrenaline level and it's a very unpleasant feeling.
Most say turn ABS off in the dirt. I agree. Although I've found in some situations, it makes things easier. Like a steep downhill that's not rugged terrain, but has a loose surface.
In general, for off road use I'd say turn it off. It's good to develop a strong feel for your brakes. ON pavement, I always leave it on.
Just remember, if you get that strange feeling in the lever and you want more stopping power... release/reapply!
2014 Ducati Multistrada 1200 Pikes Peak MNB Touring Edition
2009 BMW F800GS
2011 Husqvarna TE310 - 2003 Husqvarna TE610e
2007 HD Road King FLHR
1997 BMW K1100LT Special Edition