If I noticed this thread sooner, I would have been able to provide a response. I currently own both the Little Dot MKI and MKI+. Both of versions of Little Dot's portable amplifier are excellent and have their own character. The MKI is capable of op-amp rolling which basically means that there are customizable tweaks that can be done to the amp to provide a warmer tube-like sound character while still retaining that awesome current drive. The MKI+ doesn't have that feature, but it does have excellent dynamics. Both the MKI and MKI+ have excellent sonic qualities coming close to their tube-amps. I personally use the MKI exclusively to drive my Beyerdynamic DT990 Audiophile Reference Headphones (600-ohm Version) while the MKI+ driving the AKG K701. Moon Audio Blue Dragon Version-1 silver interconnects while I am using the Colorfly CK4 borrowed from a friend while I wait for the Little Dot DP-I to be released to the audiophile masses.
Sound stage representation, instruments separation, and overall listening experience has been excellent with both MKI and MKI+. After upgrading the op-amp on the MKI from the stock model provided by National Semiconductor to one sample provided by Linear Technologies LT1364, the dynamics have improved in a noticeable and subtle manner while coming closer to the tube-quality of the Little Dot MK-VI that I am a proud owner of.
Kind to think it, I am going start a separate thread titled Little Dot MKI/MKI+ appreciation and thoughts