I own a pair of k26p and also a pair of the k27i with the volume control.
If you can get a seal with either of these,and i say that because of the 3d axis mechanism it's sometimes difficult to seal both ears,but when you get the seal....wow.
i use these on my sony dap's S618,S638,Rz1 etc and they really perform and they are very sensitive so they dont need much volume.
In my opinion they sound better than many phones 3,4,5 times the price.
They sound better than the Shure Se530,yeah i know its an iem but that gives you some idea how they sound.
As for them being muddy ive never thought that at all.
To me they sound clear,punchy and musical and for the price they both are a complete winner in my book.