While Musks system allows for air to be in the tube system because each transporter depends on air to achieve levitation while in the tube.
There are many reasons that having air in the tube make for easier construction and maintenance.
The air vs non air debate also is a huge difference between these two different systems for the length they will be deployed. The ET3 system is meant for continental travel because of the speeds involved. While Musks system, much slower but far faster than anything in existence, would be better suited for smaller distances of less than 500 miles. Musk also said that supersonic air travel will be easier eventually for longer distances (where are my supersonic air passenger planes!?!)
So, for Colorado I think Musks system would be better. Plus, we in Colorado are already a mile high, less wind resistance! A hypothetical loop could be along the front range from Fort Collins to Pueblo.
So the big question will be where will ET3 plans to test their hyperloop transport system? Colorado? Can the system be both air evacuated and air infused to test both theories? Why hasent anybody made a small scale model to test this stuff out already?