I had them on my rockhopper which aside from riding off-road I also ride on-road. For road riding they are very comfortable with all the hand positions and allowed for more aerodynamic positions compared to the riser bars that came with the bike. However, the trekking bars aren't good for off-roading so I decided to put the riser bars back on the bike. I give up a bit in terms of aerodynamics when I ride the roads, but I don't feel like switching handlebars when I go from road riding to off-road riding.

I'm going to hold on to the trekking bars though as I'm planning on getting a Specialized Sirrus around Christmas time or early next year and will put them on that bike.