'foges', you absolutely cannot go wrong with the MKIII. The sonic capabilities and possibilities of this
wondrous head amp/line preamp are utterly amazing! As far as the MK I+ goes, make sure it is made to drive your type of headphones if you are seriously considering it. David at 'Little Dot' is a real gentleman to deal with, and is very knowledgeable and customer oriented. BTW, i'd go with...