Compared to it’s two main rivals, TouchOSC and Lemur, i think the biggest advantages that Midi Designer has is it’s ease of use (no scripting), it’s expansiveness (it can tackle very complex setups with ease), and the sublime way in which it’s been put together. It worked flawlessly for me and has already saved me about €400 for not having to buy a programming module for one of my 80’s synthesizers (the Roland D50) - I simply made my own layout. This has become a central part of my rig very quickly. It’s worth every penny.