The MKIII let me know that amping does really make a difference, but after moving to the MKVI I find myself not recommending the MKIII because I simply can't remember it giving enough of a jolt like I experienced with the MKVI.
If you follow the example, listening to headphones directly from a source is like walking. Using a MKIII is like jogging and the MKVI is like driving a car. It's an order of magnitude greater.
In hindsight I suppose the MKIII did a great service to me by opening up the world of amps to me, but I was quickly looking for an upgrade because it wasn't enough. Budget buyers beware!