I only use a weedeater near the waters edge i have to cut about 1200 feet about 1-1.5 feet wide. I try to get as close as i can with my mower. I would think one of those dr trimmer things would be more work than a weedeater close to the waters edge.
Now on a steep incline(dam) it would be alot better than a weedeater. When i bought my kubota i made sure to get a 4x4 its a world of difference between a 4x2 and a 4x4.You dont need big kahunas you just need to close your eyes.LOL

You can pay more but you cant buy better.