If you use the built in browser in Notation Player, it downloads files to the programme's default "Tunes" directory and as soon as downloaded, automatically converts the midi information into the format it displays as a music score, which it displays.
I presume that makes it quicker than Noteworthy for you to see an image on screen.
I have just had a quick scan through the prog's "Help" file, and it seems that the inbuilt browser is actually a version of Internet Explorer, framed in the Player. It is set to download to it's own settings rather than the settings of the standard IE.
It doesn't seem to be a big programme, and I haven't noticed any clashes with software on my computer.
I personally think it isone worth having to give a quick preview of MIDI files as dots.
Quack!
GtD.