Holy wars have been started over such a question !! (okay, personal bias: I have to admit here I don't regularly use the RopeWrench or the ZigZag)
1. For me the Rope Runner is still the best all around , great control and works over a wide range of different ropes, body weights, even if you add a 660 on your harness while working a big spar down. I have three of the four I have acquired over the years, having gifted one to a friend.
2. The Hitchhiker runs a close second and is also great for control, though not as fun for flips and burning out as the RopeRunner. I have two of them, having gifted one to a friend.
3. I love the Akimbo, but rank it third in my arsenal as I find it a bit more temperamental (really splitting hairs here, they are all great climbing devices, and if I had to choose just one I'd have a hard time). Some find they are always adjusting the friction settings, even over a single long climb, if the humidity changes, or as a rope stretches and flattens. It is a bit worse in the rain and a pitchy tree can lead to a full stop situation. I still climb on the "Go-Fund-Me" original Akimbo, and based upon what others have said about their Rock Exotika (RE) version I have not bothered to get one yet.
That being said, the Akimbo being mid-line-attachable is the bomb; especially for doing crane jobs where you are relocating your TIP from the hook to the spar, and back, etc. You'll perhaps find an alternative HUT helps with the RE Akimbo, too.
The ease of use of the Akimbo makes me lazy. Unless I know I need the cutting edge all-out-blazing-rip-roaring benefits of the RopeRunner, I simply pop open the Akimbo lay in the rope, and I am on my way. It is a joy to use. And the older I get the less "Johnny Pro" I get and the more Akimbo I find I am...
Johnny Pro: