The one arm row (OAR) is a great back exercise. It's a staple in my training routines. Not only do I do it myself but I put it into the programs I design for others.
I'm not a big fan of the bent over row. But I do include it in my training from time to time because of the big loads that can be used and the overhand grip.
What I have found to be a great alternative to the the bent over row is what I like to call the Business End Landmine Row.
Withe the BELM you can load up the weight and use the pronated grip to get more back activation.
If your dumbbells don't go up that high this exercise is a must.
If you want to get an incredible grip workout do a few burnout sets without straps. This will set your forearms on fire.
For the heavier sets straps are needed.
Check out the Business End Landmine Row and let me know what you think.