I only model aircraft as a hobby, so I am not going to do anything with it other than render, print and maybe hang it on my wall!

Modo is a very different type of modeller to MoI so the UI requirements are very different as well. There have been many threads on here where Michael discusses the difference between a Nurbs modeller like MoI and sub-d polygon modellers like Modo.

For ease of use, MoI stands out amongst Nurbs modellers. I also use Alias Design, which is far more powerful than MoI in the Nurbs surfacing field, but is probably the hardest UI I have ever had the misfortune to learn.

Modo is designed to have a very fast workflow when modelling in sub-d but because of that, it is not as easy to learn as Cinema 4D.