It makes for a more acidic brew, which I personally really like. It's quite fruity as well, while still definitely being coffee.
Based on your recommendations, it might not be your cup of tea (or in this case, coffee!), but it might be worth a try if you want to expand your horizons. I am personally not into dark roasts, being mostly a medium to light-roast person.
That seems like a great way to plug your own drains.
Also, I was under the impression that restaurants could sell their frying oil for recycling? This is a weakly held impression to be sure but I want to remember reading something about it.